Exhibit 1.1

EXECUTION VERSION

2,725,000 Shares

CLEAN DIESEL TECHNOLOGIES, INC.

Common Stock

UNDERWRITING AGREEMENT

June 28, 2011

Roth Capital Partners, LLC

As Representative of
the Underwriters named in
Schedule I

c/o Roth Capital Partners, LLC
24 Corporate Plaza
Newport Beach, CA 92660

Ladies and Gentlemen:

Clean Diesel Technologies, Inc. a Delaware corporation (the “ Company ”), proposes, subject to the terms and conditions stated herein, to issue and sell to the underwriters listed in Schedule I hereto (the “ Underwriters ”) an aggregate of 2,645,000 authorized but unissued shares (the “ Underwritten Shares ”) of common stock, par value $0.01 per share (the “ Common Stock ”), of the Company, and the stockholders of the Company listed on Schedule II hereto (the “ Selling Stockholders ” and each a “ Selling Stockholder ”), hereby agree, severally but not jointly, to sell an aggregate of up to 80,000 shares of Common Stock (the “ Secondary Shares ”) in the amounts set forth opposite their names on Schedule II. The Company has granted the Underwriters the option to purchase an aggregate of up to 408,750 additional shares of Common Stock (the “ Additional Shares ”) as may be necessary to cover any over-allotments made in connection with the offering. The Underwritten Shares, Secondary Shares and Additional Shares are collectively referred to as the “ Shares .” Roth Capital Partners, LLC has agreed to act as the representative of the Underwriters (in such capacity, the “ Representative ”) in connection with the offering and sale of the Shares.

The Company, the Selling Stockholders and the Underwriters hereby confirm their agreement as follows:

1. Registration Statement and Prospectus . The Company has prepared and filed with the Securities and Exchange Commission (the “ Commission ”) a registration statement on Form S-1 (File No. 333-174680) under the Securities Act of 1933, as amended (the “ Securities Act ”) and the rules and regulations (the “ Rules and Regulations ”) of the Commission thereunder, and such amendments to such registration statement (including post effective amendments) as may have been required to the date of this Agreement and a preliminary prospectus or “red herring” pursuant to Rule 424(b) under the Securities Act. Such registration statement, as amended (including any post effective amendments), has been declared effective by the Commission. Such registration statement, including amendments thereto (including post effective amendments thereto), the exhibits and any schedules thereto and the documents

and information otherwise deemed to be a part thereof or included or incorporated by reference therein by the Securities Act or otherwise pursuant to the Rules and Regulations, is herein called the “ Registration Statement .” If the Company has filed or files an abbreviated registration statement pursuant to Rule 462(b) under the Securities Act (the “ Rule 462 Registration Statement ”), then any reference herein to the term Registration Statement shall include such Rule 462 Registration Statement. Any preliminary prospectus included in the Registration Statement or filed with the Commission pursuant to 424(a) under the Securities Act is hereinafter called a “ Preliminary Prospectus .” The Preliminary Prospectus relating to the Shares that was included in the Registration Statement immediately prior to the pricing of the offering contemplated hereby is hereinafter called the “ Pricing Prospectus .”

The Company is filing with the Commission pursuant to Rule 424 under the Securities Act a final prospectus relating to the Shares and such final prospectus, as filed, is hereinafter called the “ Final Prospectus .” The Final Prospectus, the Pricing Prospectus and any preliminary prospectus or “red herring” in the form in which they were included in the Registration Statement or filed with the Commission pursuant to Rule 424 under the Securities Act is hereinafter called a “ Prospectus .”

For purposes of this Agreement, all references to the Registration Statement, the Rule 462 Registration Statement, the Pricing Prospectus, the Final Prospectus, the Prospectus or any amendment or supplement to any of the foregoing shall be deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis, and Retrieval system (“ EDGAR ”). All references in this Agreement to amendments to the Registration Statement, the Rule 462 Registration Statement, the Pricing Prospectus, the Final Prospectus or the Prospectus shall be deemed to mean and include any document filed by the Company under the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), that is incorporated by reference therein or otherwise deemed by the Rules and Regulations to be a part thereof.

2. Representations and Warranties of the Company Regarding the Offering.

(a) The Company represents and warrants to, and agrees with, the Underwriters, as of the date hereof and as of the Closing Date (as defined in Section 5(c) below), except as otherwise indicated, as follows:

(i) At each time of effectiveness, at the date hereof and at the Closing Date, the Registration Statement and any post-effective amendment thereto complied or will comply in all material respects with the requirements of the Securities Act and the Rules and Regulations and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading. The Time of Sale Disclosure Package (as defined in Section 2(a)(iii)(A)(1) below) as of the date hereof and at the Closing Date, any roadshow or investor presentations delivered by the Company to and approved by the Representative for use in connection with the marketing of the offering

of the Shares (the “ Marketing Materials ”) when taken together with the Time of Sale Disclosure Package as of the time of their use and at the Closing Date, and the Final Prospectus, as amended or supplemented, as of its date, at the time of filing pursuant to Rule 424(b) under the Securities Act and at the Closing Date, did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. The representations and warranties set forth in the two immediately preceding sentences shall not apply to statements in or omissions from the Registration Statement or any Prospectus in reliance upon, and in conformity with, written information furnished to the Company by the Representative specifically for use in the preparation thereof, which written information is described in Section 8(g). The Registration Statement contains all exhibits and schedules required to be filed by the Securities Act or the Rules and Regulations. No order preventing or suspending the effectiveness or use of the Registration Statement or any Prospectus is in effect and no proceedings for such purpose have been instituted or are pending, or, to the knowledge of the Company, are contemplated or threatened by the Commission.

(ii) The Company has not distributed any prospectus or other offering material in connection with the offering and sale of the Shares other than the Time of Sale Disclosure Package and the Marketing Materials.

(iii) (A) The Company has provided a copy to the Representative of each Issuer Free Writing Prospectus (as defined below) used in the sale of Shares. The Company has filed all Issuer Free Writing Prospectuses required to be so filed with the Commission, and no order preventing or suspending the effectiveness or use of any Issuer Free Writing Prospectus is in effect and no proceedings for such purpose have been instituted or are pending, or, to the knowledge of the Company, are contemplated or threatened by the Commission. When taken together with the rest of the Time of Sale Disclosure Package or the Final Prospectus, since its first use and at all relevant times since then, no Issuer Free Writing Prospectus has, does or will include (1) any untrue statement of a material fact or omission to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or (2) information that conflicted, conflicts or will conflict with the information contained in the Registration Statement or the Final Prospectus. The representations and warranties set forth in the immediately preceding sentence shall not apply to statements in or omissions from the Time of Sale Disclosure Package, the Final Prospectus or any Issuer Free Writing Prospectus in reliance upon, and in conformity with, written information furnished to the Company by the Representative specifically for use in the preparation thereof. As used in this paragraph and elsewhere in this Agreement:

(1) “ Time of Sale Disclosure Package ” means the Pricing Prospectus, each Issuer Free Writing Prospectus, and any description of the transaction provided by the Representative included on Schedule III .

(2) “ Issuer Free Writing Prospectus ” means any “issuer free writing prospectus,” as defined in Rule 433 under the Securities Act, relating to the Shares that (A) is required to be filed with the Commission by the Company, or (B) is exempt from filing pursuant to Rule 433(d)(5)(i) or (d)(8) under the Securities Act, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g) under the Securities Act.

(B) At the time of filing of the Registration Statement and at the date hereof, the Company was not and is not an “ineligible issuer,” as defined in Rule 405 under the Securities Act or an “excluded issuer” as defined in Rule 164 under the Securities Act.

(C) Each Issuer Free Writing Prospectus satisfied, as of its issue date and at all subsequent times through the Prospectus Delivery Period (as defined in Section 6(a)(i) below), all other conditions as may be applicable to its use as set forth in Rules 164 and 433 under the Securities Act, including any legend, record-keeping or other requirements.

(iv) The consolidated financial statements of the Company, together with the related notes, included or incorporated by reference in the Registration Statement, the Time of Sale Disclosure Package and the Final Prospectus comply in all material respects with the applicable requirements of the Securities Act and the Exchange Act and fairly present the financial condition of the Company as of the dates indicated and the results of operations and changes in cash flows for the periods therein specified in conformity with generally accepted accounting principles consistently applied throughout the periods involved present fairly the information required to be stated therein. No other financial statements, pro forma financial information or schedules are required under the Securities Act to be included or incorporated by reference in the Registration Statement, the Time of Sale Disclosure Package or the Final Prospectus. To the Company’s knowledge, KPMG LLP, which has expressed its opinion with respect to the consolidated financial statements filed as a part of the Registration Statement and included in the Registration Statement, the Time of Sale Disclosure Package and the Final Prospectus, is an independent public accounting firm with respect to the Company within the meaning of the Securities Act and the Rules and Regulations.

(v) The Company had a reasonable basis for, and made in good faith, each “forward-looking statement” (within the meaning of Section 27A of the Act or Section 21E of the Exchange Act) contained or incorporated by reference in the Registration Statement, the Time of Sale Disclosure Package, the Final Prospectus or the Marketing Materials.

(vi) All statistical or market-related data included or incorporated by reference in the Registration Statement, the Time of Sale Disclosure Package or the Final Prospectus, or included in the Marketing Materials, are based on or derived from sources that the Company reasonably believes to be reliable and accurate, and the Company has obtained the written consent to the use of such data from such sources, to the extent required.

(vii) The Common Stock is registered pursuant to Section 12(b) of the Exchange Act and is included or approved for inclusion on The NASDAQ Capital Market. There is no action pending by the Company or, to the Company’s knowledge, The NASDAQ Stock Market LLC, to delist the Common Stock from The NASDAQ Capital Market, nor has the Company received any notification that The NASDAQ Stock Market LLC is contemplating terminating such listing. When issued, the Shares will be listed on The NASDAQ Capital Market.

(viii) The Company has not taken, directly or indirectly, any action that is designed to or that has constituted or that would reasonably be expected to cause or result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares.

(ix) The Company is not and, after giving effect to the offering and sale of the Shares and the application of the net proceeds thereof, will not be an “investment company,” as such term is defined in the Investment Company Act of 1940, as amended.

(b) Any certificate signed by any officer of the Company and delivered to the Representative or to the Representative’s counsel in connection with the offering of Shares contemplated hereby shall be deemed a representation and warranty by the Company to the Underwriters as to the matters covered thereby.

3. Representations and Warranties Regarding the Company.

(a) The Company represents and warrants to and agrees with, the Underwriters, except as set forth in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus, as follows:

(i) Each of the Company and its Significant Subsidiaries (which has the meaning set forth in Rule 1-02 of Regulation S-X) has been duly organized and is validly existing as a corporation in good standing under the laws of its jurisdiction of incorporation. Each of the Company and its Significant Subsidiaries has the corporate power and authority to own its properties and conduct its business as currently being carried on and as described in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus, and is duly qualified to do business as a foreign corporation in good standing in each jurisdiction in which it owns or leases real property or in which the conduct of its business makes such qualification necessary and in which the failure to so qualify would have or is reasonably likely to result in a material adverse effect upon the business, prospects, properties, operations, condition (financial or otherwise) or results of operations of the Company and its subsidiaries, taken as a whole, or in its ability to perform its obligations under this Agreement (“ Material Adverse Effect ”).

(ii) The Company has the power and authority to enter into this Agreement and to authorize, issue and sell the Shares as contemplated by this Agreement. This Agreement has been duly authorized, executed and delivered by the Company, and constitutes a valid, legal and binding obligation of the Company, enforceable against the Company in accordance with its terms, except as rights to indemnity hereunder may be limited by federal or state securities laws and except as such enforceability may be limited by bankruptcy, insolvency, reorganization or similar laws affecting the rights of creditors generally and subject to general principles of equity.

(iii) The execution, delivery and performance of this Agreement and the consummation of the transactions herein contemplated will not (A) result in a breach or violation of any of the terms and provisions of, or constitute a default under, any law, rule or regulation to which the Company or any Significant Subsidiary is subject, or by which any property or asset of the Company or any Significant Subsidiary is bound or affected, (B) conflict with, result in any violation or breach of, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, or give to others any right of termination, amendment, acceleration or cancellation (with or without notice, lapse of time or both) of, any agreement, lease, credit facility, debt, note, bond, mortgage, indenture or other instrument (the “ Contracts ”) or obligation or other understanding to which the Company or any Significant Subsidiary is a party of by which any property or asset of the Company or any Significant Subsidiary is bound or affected, except to the extent that such conflict, default, termination, amendment, acceleration or cancellation right is not reasonably likely to result in a Material Adverse Effect, or (C) result in a breach or violation of any of the terms and provisions of, or constitute a default under, the Company’s charter or by-laws.

(iv) Neither the Company nor any of its Significant Subsidiaries is in violation, breach or default under its certificate of incorporation, by-laws or other equivalent organizational or governing documents, except where the violation, breach or default in the case of a Significant Subsidiary of the Company is not reasonably likely to result in a Material Adverse Effect.

(v) All consents, approvals, orders, authorizations and filings required on the part of the Company and its subsidiaries in connection with the execution, delivery or performance of this Agreement have been obtained or made, other than such consents, approvals, orders and authorizations the failure of which to make or obtain is not reasonably likely to result in a Material Adverse Effect.

(vi) All of the issued and outstanding shares of capital stock of the Company are duly authorized and validly issued, fully paid and nonassessable, and have been issued in compliance with all applicable securities laws, and conform to the description thereof in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus. Except for the issuances of options or restricted stock or restricted stock units in the ordinary course of business, since the respective dates as of which information is provided in the Registration Statement, the Time of Sale Disclosure Package or the Prospectus, the Company has not entered into or granted any convertible or exchangeable securities, options, warrants, agreements, contracts or other rights in existence to purchase or acquire from the Company any shares of the capital stock of the Company. The Shares, when issued, will be duly authorized and validly issued, fully paid and nonassessable, will be issued in compliance with all applicable securities laws, and will be free of preemptive, registration or similar rights.

(vii) Each of the Company and its Significant Subsidiaries has filed all returns (as hereinafter defined) required to be filed with taxing authorities prior to the date hereof or has duly obtained extensions of time for the filing thereof. Each of the Company and its Significant Subsidiaries has paid all taxes (as hereinafter defined) shown as due on such returns that were filed and has paid all taxes imposed on or assessed against the Company or such respective Significant Subsidiary. The provisions for taxes payable, if any, shown on the consolidated financial statements filed with or as part of the Registration Statement are sufficient for all accrued and unpaid taxes, whether or not disputed, and for all periods to and including the dates of such consolidated financial statements. Except as disclosed in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus, (i) no issues have been raised (and are currently pending) by any taxing authority in connection with any of the returns or taxes asserted as due from the Company or its Significant Subsidiaries, and (ii) no waivers of statutes of limitation with respect to the returns or collection of taxes have been given by or requested from the Company or its Significant Subsidiaries. The term “ taxes ” mean all federal, state, local, foreign, and other net income, gross income, gross receipts, sales, use, ad valorem, transfer, franchise, profits, license, lease, service, service use, withholding, payroll, employment, excise, severance, stamp, occupation, premium, property, windfall profits, customs, duties or other taxes, fees, assessments, or charges of any kind whatever, together with any interest and any penalties, additions to tax, or additional amounts with respect thereto. The term “ returns ” means all returns, declarations, reports, statements, and other documents required to be filed in respect to taxes.

(viii) Since the respective dates as of which information is given in the Registration Statement, the Time of Sale Disclosure Package or the Prospectus, (a) neither the Company nor any of its Significant Subsidiaries has incurred any material liabilities or obligations, direct or contingent, or entered into any material transactions other than in the ordinary course of business, (b) the Company has not declared or paid any dividends or made any distribution of any kind with respect to its capital stock; (c) there has not been any change in the capital stock of the Company or any of its Significant Subsidiaries (other than a change in the number of outstanding shares of Common Stock due to the issuance of shares upon the exercise of outstanding convertible notes, options or warrants or the issuance of restricted stock awards or restricted stock units under the Company’s existing stock awards plan, or any new grants thereof in the ordinary course of business), (d) other than the possible sale of additional accounts receivable pursuant to its $7.5 million demand credit facility there has not been any material change in the Company’s long-term or short-term debt, and (e) there has not been the occurrence of any Material Adverse Effect.

(ix) The Company makes and keeps accurate books and records and maintains a system of internal accounting controls sufficient to provide reasonable assurance that (a) transactions are executed in accordance with management’s general or specific authorization, (b) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles, consistently applied and to maintain accountability for assets, (c) access to assets is permitted only in accordance with management’s general or specific authorization and (d) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences. Except as disclosed in the Time of Sale Disclosure Package, there has not been a material weakness in the Company’s internal control over financial reporting (whether or not remediated) and since January 1, 2011, and there has been no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(x) The Company has established and maintains disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)), which (a) are designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is made known to the Company’s principal executive officer and its principal financial officer by others within those entities, particularly during the periods in which the periodic reports required under the Exchange Act are being prepared and (b) are effective in all material respects to perform the functions for which they were established. The Company is not aware of any fraud, whether or not material, that involves management or other employees who have a significant role in the Company’s internal control over financial reporting with respect to the Company’s internal control over financial reporting.

(xi) There is no pending or, to the knowledge of the Company, any threatened, action, suit or proceeding to which the Company or any of its Significant Subsidiaries is a party or of which any property or assets of the Company or its subsidiaries is the subject of before or by any court or governmental agency, authority or body, or any arbitrator or mediator, which is reasonably likely to result in a Material Adverse Effect.

(xii) The Company and each of its Significant Subsidiaries holds, and is in compliance with, all franchises, grants, authorizations, licenses, permits, easements, consents, certificates and orders (“ Permits ”) of any governmental or self-regulatory agency, authority or body required for the conduct of its business, and all such Permits are in full force and effect, in each case except where the failure to hold, or comply with, any of them is not reasonably likely to result in a Material Adverse Effect.

(xiii) The Company and each of its Significant Subsidiaries is in material compliance with all Environmental Laws. As used herein, “Environmental Law(s)” means any and all applicable international, federal, state, or local laws, statutes, ordinances, regulations, policies, guidance, rules, judgments, orders, court decisions or rule of common law, permits, restrictions and licenses, that (i) regulate or relate to the protection or clean up of the environment; the use, treatment, storage, transportation, handling, disposal or release of Hazardous Substances, the preservation or protection of waterways, groundwater, drinking water, air, wildlife, plants or other natural resources; or the health and safety of persons or property, including without limitation protection of the health and safety of employees; or (ii) impose liability or responsibility with respect to any of the foregoing, including without limitation the Comprehensive Environmental Response, Compensation and Liability Act (42 U.S.C. § 9601 et seq.), or any other law of similar effect. As used herein, “Hazardous Substances” means any pollutant, chemical, substance and any toxic, infectious, carcinogenic, reactive, corrosive, ignitable or flammable chemical, or chemical compound, or hazardous substance, material or waste, whether solid, liquid or gas, that is subject to regulation, control or remediation under any Environmental Laws, including without limitation, any quantity of asbestos in any form, urea formaldehyde, PCBs, radon gas, crude oil or any fraction thereof, all forms of natural gas, petroleum products or by-products or derivatives.

(xiv) There has not been any Hazardous Substances used, generated, treated, stored, disposed of, released, handled or otherwise existing on any property that has been owned, leased or operated by the Company or its Significant Subsidiaries except in compliance with all Environmental Laws, other than such noncompliance that is not reasonably likely to result in a Material Adverse Effect.

(xv) Neither the Company nor any of its Significant Subsidiaries has received any communication, whether from a governmental authority, citizens group, employee or otherwise, that alleges that the Company or any of its Significant Subsidiaries is not in material compliance with any Environmental Laws, and, to the Company’s knowledge, there are no circumstances that could reasonably be expected to prevent or interfere with such compliance in the future. There are no material environmental claims pending or threatened against the Company or any of its Significant Subsidiaries, nor is the Company aware of any information which might form the basis of any such claims.

(xvi) The Company has made available all material environmental assessments, reports, data, results of investigations, audits and other material documents in the possession or control of the Company or any of its Significant Subsidiaries regarding environmental matters pertaining to the environmental condition of any real properties owned or operated by the Company or any of its Significant Subsidiaries, any environmental claims respecting the Company or any of its Significant Subsidiaries, or any noncompliance by the Company or any of its Significant Subsidiaries with any Environmental Laws.

(xvii) The Company and its Significant Subsidiaries have good and marketable title to all property (whether real or personal) described in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus as being owned by them that are material to the business of the Company, in each case free and clear of all liens, claims, security interests, other encumbrances or defects, except those that are not reasonably likely to result in a Material Adverse Effect. The property held under lease by the Company and its Significant Subsidiaries is held by them under valid, subsisting and enforceable leases with only such exceptions with respect to any particular lease as are not material or do not interfere in any material respect with the conduct of the business of the Company and its subsidiaries.

(xviii) The Company and each of its Significant Subsidiaries owns or possesses or has valid right to use all patents, patent applications, trademarks, service marks, trade names, trademark registrations, service mark registrations, copyrights, licenses, inventions, trade secrets and similar rights (“ Intellectual Property ”) necessary for the conduct of the business of the Company and its subsidiaries as currently carried on and as described in the Registration Statement, the Time of Sale Disclosure Package and the Prospectus. To the knowledge of the Company, no action or use by the Company or any of its Significant Subsidiaries involves or gives rise to any infringement of, or license or similar fees for, any Intellectual Property of others, except where such action, use, license or fee is not reasonably likely to result in a Material Adverse Effect. Neither the Company nor any of its Significant Subsidiaries has received any notice alleging any such infringement or fee.

(xix) The Company and each of its subsidiaries has complied with, is not in violation of, and has not received any notice of violation relating to any law, rule or regulation relating to the conduct of its business, or the ownership or operation of its property and assets, including, without limitation, (A) the Currency and Foreign Transactions Reporting Act of 1970, as amended, or any money laundering laws, rules or regulations, (B) the Sarbanes-Oxley Act and the rules and regulations of the Commission thereunder, (C) the Foreign Corrupt Practices Act of 1977 and the rules and regulations thereunder, and (D) the Employment Retirement Income Security Act of 1974 and the rules and regulations thereunder, in each case except where the failure to be in compliance is not reasonably likely to result in a Material Adverse Effect.

(xx) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, employee, representative, agent or affiliate of the Company or any of its subsidiaries is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“ OFAC ”); and the Company will not directly or indirectly use the proceeds of the offering of the Shares contemplated hereby, or lend, contribute or otherwise make available such proceeds to any person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(xxi) The Company and each of its Significant Subsidiaries carries, or is covered by, insurance in such amounts and covering such risks as the Company reasonably believes is adequate for the conduct of its business and the value of its properties.

(xxii) No labor dispute with the employees of the Company or any of its Significant Subsidiaries exists or, to the knowledge of the Company, is imminent that is reasonably likely to result in a Material Adverse Effect.

(xxiii) No supplier or customer of the Company has notified the Company that it intends to discontinue or decrease the rate of business done with the Company in such a way that such discontinuation or decrease is reasonably likely to result in a Material Adverse Effect. In addition, neither the Company nor its Significant Subsidiaries have experienced and, to the Company’s knowledge, there does not exist, any material quality control or similar problems with any of the products and/or services currently being supplied to the Company or any of its Significant Subsidiaries by any of its suppliers such that such material quality control or similar problem is reasonably likely to result in a Material Adverse Effect.

(xxiv) There are no claims, payments, issuances, arrangements or understandings for services in the nature of a finder’s, consulting or origination fee with respect to the introduction of the Company to the Underwriters or the sale of the Shares hereunder or any other arrangements, agreements, understandings, payments or issuances with respect to the Company that may affect the Underwriters’ compensation, as determined by FINRA.

(xxv) Except as disclosed to the Representative in writing, the Company has not made any direct or indirect payments (in cash, securities or otherwise) to (i) any person, as a finder’s fee, investing fee or otherwise, in consideration of such person raising capital for the Company or introducing to the Company persons who provided capital to the Company, (ii) any FINRA member, or (iii) any person or entity that has any direct or indirect affiliation or association with any FINRA member within the 12-month period prior to the date on which the Registration Statement was filed with the Commission (“Filing Date”) or thereafter.

(xxvi) None of the net proceeds of the offering will be paid by the Company to any participating FINRA member or any affiliate or associate of any participating FINRA member, except as specifically authorized herein.

(xxvii) No person has the right to require the Company or any of its subsidiaries to register any securities for sale under the Securities Act by reason of the filing of the Registration Statement with the Commission or the issuance and sale of the Shares, except as otherwise have been waived in connection with the issuance and sale of the Shares contemplated hereby.

(xxviii) To the Company’s knowledge, no (i) officer or director of the Company or its subsidiaries, (ii) owner of 5% or more of the Company’s unregistered securities or that of its subsidiaries or (iii) owner of any amount of the Company’s unregistered securities acquired within the 180-day period prior to the Filing Date, has any direct or indirect affiliation or association with any FINRA member. The Company will advise the Representative and its counsel if it becomes aware that any officer, director or stockholder of the Company or its subsidiaries is or becomes an affiliate or associated person of a FINRA member participating in the offering.

(xxix) Other than the Underwriters, no person has the right to act as an underwriter or as a financial advisor to the Company in connection with the transactions contemplated hereby.

4. Representations and Warranties of the Selling Stockholders.

(a) Each Selling Stockholder, severally and not jointly, represents and warrants to, and agrees with, the Underwriters as follows:

(i) This Agreement has been duly authorized, executed and delivered by such Selling Stockholder, and constitutes a valid, legal and binding obligation of such Selling Stockholder, enforceable in accordance with its terms, except as rights to indemnity hereunder may be limited by federal or state securities laws and except as such enforceability may be limited by bankruptcy, insolvency, reorganization or similar laws affecting the rights of creditors generally and subject to general principles of equity. The execution, delivery and performance of this Agreement and the consummation of the transactions herein contemplated will not result in a breach or violation of any of the terms and provisions of, or constitute a default under, any statute, agreement or instrument to which such Selling Stockholder is a party or by which it is bound or to which any of its property is subject, or any order, rule, regulation or decree of any court or governmental agency or body having jurisdiction over such Selling Stockholder or any of its properties, except for violations and defaults that individually or in the aggregate would not reasonably be expected to have a Material Adverse Effect. The execution, delivery and performance of this Agreement and the consummation of the transactions herein contemplated will not result in a breach or violation of any of the terms and provisions of, or constitute a default under, such Selling Stockholder’s charter or by-laws. No consent, approval, authorization or order of, or filing with, any court or governmental agency or body is required for the execution, delivery and performance of this Agreement or for the consummation of the transactions contemplated hereby, including the sale of the Shares by such Selling Stockholder, except as may be required under the Securities Act or state securities or blue sky laws; and such Selling Stockholder has the power and authority to enter into this Agreement and to sell the Shares as contemplated by this Agreement.

(ii) Such Selling Stockholder is, on the date hereof, the record and beneficial owner of all of the Shares to be sold by the Selling Stockholder hereunder free and clear of all liens, encumbrances, equities and claims and has duly indorsed such Shares in blank or has duly signed a stock power assigning all right, title and interest to the Shares to be sold by such Selling Stockholder, with all signatures appropriately guaranteed by an eligible guarantor institution with membership in an approved medallion guaranty program pursuant to Rule 17Ad-15 under the Exchange Act.

(iii) On the applicable Closing Date, all stock transfer or other taxes (other than income taxes) that are required to be paid in connection with the sale and transfer by such Selling Stockholder of the Shares will be fully paid or provided for by such Selling Stockholder and all laws imposing such taxes will be fully complied with.

(iv) Such Selling Stockholder, directly or indirectly, has not entered into any commitment, transaction or other arrangement, including any prepaid forward contract, 10b5-1 plan or similar agreement, which transfers or may transfer any of the legal or beneficial ownership or any of the economic consequences of ownership of the Shares, except as has been previously disclosed in writing to the Representative.

(v) Such Selling Stockholder represents and warrants that it has not prepared or had prepared on its behalf or used or referred to any “free writing prospectus” (as defined in Rule 405 of the Act) and further represents that it has not distributed and will not distribute any written materials in connection with the offer or sale of the Shares that could otherwise constitute a “free writing prospectus” (as defined in Rule 405 of the Act) required to be filed with the Commission or retained under Rule 433 of the Act.

(vi) All information relating to such Selling Stockholder furnished by or on behalf of such Selling Stockholder in writing expressly for use in the Registration Statement, the Time of Sale Disclosure Package or any Prospectus, as the case may be, is as of the applicable Closing Date, true, correct, and complete in all material respects, and does not, and will not, contain any untrue statement of a material fact or omit to state any material fact necessary to make such information not misleading. In addition, such Selling Stockholder confirms as accurate the number of shares of Common Stock set forth opposite such Selling Stockholder’s name in the Time of Sale Disclosure Package and any Prospectus under the caption “Principal and Selling Stockholders” (both prior to and after giving effect to the sale of the Shares).

(vii) Such Selling Stockholder does not have any registration or other similar rights to have any equity or debt securities registered for sale by the Company under the Registration Statement or included in an offering contemplated by this Agreement, except for such rights that have been waived.

(viii) Such Selling Stockholder has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares in violation of the Act or the Exchange Act.

(ix) Such Selling Stockholder is not prompted to sell shares of Common Stock by any information concerning the Company that is not set forth in the Registration Statement, the Time of Sale Disclosure Package or a Prospectus.

(b) Any certificate signed by any officer of a Selling Stockholder and delivered to the Representative or to the Representative’s counsel shall be deemed a representation and warranty by such Selling Stockholder to the Underwriters as to the matters covered thereby and shall not be deemed to be a representation and warranty of such person in an individual capacity.

5. Purchase, Sale and Delivery of Shares.

(a) On the basis of the representations, warranties and agreements herein contained, but subject to the terms and conditions herein set forth, the Company agrees to issue and sell the Underwritten Shares and the Selling Stockholders agree to sell the Secondary Shares to the Underwriters, and the Underwriters agree, severally and not jointly, to purchase the Underwritten Shares and Secondary Shares. The purchase price for each Underwritten Share and Secondary Share shall be $3.5208 per share (the “ Per Share Price ”).

(b) The Company hereby grants to the Underwriters the option to purchase some or all of the Additional Shares and, upon the basis of the warranties and representations and subject to the terms and conditions herein set forth, the Underwriters shall have the right to purchase all or any portion of the Additional Shares at the Per Share Price as may be necessary to cover any over-allotments made in connection with the transactions contemplated hereby. This option may be exercised by the Representative at any time (but not more than once) on or before the thirtieth day following the date hereof, by written notice to the Company (the “ Option Notice ”). The Option Notice shall set forth the aggregate number of Additional Shares as to which the option is being exercised, and the date and time when the Additional Shares are to be delivered (such date and time being herein referred to as the “ Option Closing Date ”); provided , however , that the Option Closing Date shall not be earlier than the Closing Date (as defined below) nor earlier than the first business day after the date on which the option shall have been exercised nor later than the fifth business day after the date on which the option shall have been exercised unless the Company and the Representative otherwise agree.

Payment of the purchase price for and delivery of the Additional Shares shall be made at the Option Closing Date in the same manner and at the same office as the payment for the Underwritten Shares as set forth in subparagraph (c) below.

(c) The Underwritten Shares and Secondary Shares will be delivered by the Company and the Selling Stockholders to the Representative for the account of the Underwriters against payment of the purchase price therefor by wire transfer of same day funds payable to the order of the Company or a Selling Stockholder, as appropriate, at the offices of Roth Capital Partners, LLC, 24 Corporate Plaza, Newport Beach, CA 92660, or such other location as may be mutually acceptable, at 6:00 a.m. PST, on the third (or if the Underwritten Shares and Secondary Shares are priced, as contemplated by Rule 15c6-1(c) under the Exchange Act, after 4:30 p.m. Eastern time, the fourth) full business day following the date hereof, or at such other time and date as the Representative and the Company determine pursuant to Rule 15c6-1(a) under the Exchange Act, or, in the case of the Additional Shares, at such date and time set forth in the Option Notice. The time and date of delivery of the Underwritten Shares and the Secondary Shares or the Additional Shares, as applicable, is referred to herein as the “ Closing Date .” If the Representative so elects, delivery of the Underwritten Shares, Secondary Shares and Additional Shares may be made by credit through full fast transfer to the account at The Depository Trust Company designated by the Representative.

6. Covenants.

(a) The Company covenants and agrees with the Underwriters as follows:

(i) During the period beginning on the date hereof and ending on the later of the Closing Date or such date as determined by the Representative the Prospectus is no longer required by law to be delivered in connection with sales by an underwriter or dealer (the “ Prospectus Delivery Period ”), prior to amending or supplementing the Registration Statement, including any Rule 462 Registration Statement, the Time of Sale Disclosure Package or the Prospectus, the Company shall furnish to the Representative for review and comment a copy of each such proposed amendment or supplement, and the Company shall not file any such proposed amendment or supplement to which the Representative reasonably objects.

(ii) From the date of this Agreement until the end of the Prospectus Delivery Period, the Company shall promptly advise the Representative in writing (A) of the receipt of any comments of, or requests for additional or supplemental information from, the Commission, (B) of the time and date of any filing of any post-effective amendment to the Registration Statement or any amendment to the Time of Sale Disclosure Package, the Prospectus or any Issuer Free Writing Prospectus, (C) of the time and date that any post-effective amendment to the Registration Statement becomes effective and (D) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order preventing or suspending its use or the use of the Time of Sale Disclosure Package or any Issuer Free Writing Prospectus, or of any proceedings to remove, suspend or terminate from listing the Common Stock from any securities exchange upon which it is listed for trading, or of the threatening or initiation of any proceedings for any of such purposes. If the Commission shall enter any such stop order at any time during the Prospectus Delivery Period, the Company will use its reasonable efforts to obtain the lifting of such order as promptly as reasonably possible. Additionally, the Company agrees that it shall comply with the provisions of Rules 424(b), 430A and 430B, as applicable, under the Securities Act and will use its reasonable efforts to confirm that any filings made by the Company under Rule 424(b) or Rule 433 were received in a timely manner by the Commission (without reliance on Rule 424(b)(8) or 164(b) of the Securities Act).

(iii) (A) During the Prospectus Delivery Period, the Company will comply with all requirements imposed upon it by the Securities Act, as now and hereafter amended, and by the Rules and Regulations, as from time to time in force, and by the Exchange Act, as now and hereafter amended, so far as necessary to permit the continuance of sales of or dealings in the Shares as contemplated by the provisions hereof, the Time of Sale Disclosure Package, the Registration Statement and the Prospectus. If during such period any event occurs the result of which the Prospectus (or if the Prospectus is not yet available to prospective purchasers, the Time of Sale Disclosure Package ) would include an untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances then existing, not misleading, or if during such period it is necessary or appropriate in the opinion of the Company or its counsel or the Representative or its counsel to amend the Registration Statement or supplement the Prospectus (or if the Prospectus is not yet available to prospective purchasers, the Time of Sale Disclosure Package ) to comply with the Securities Act, the Company will promptly notify the Representative, allow the Representative the opportunity to provide reasonable comments on such amendment, Prospectus supplement or document, and will amend the Registration Statement or supplement the Prospectus (or if the Prospectus is not yet available to prospective purchasers, the Time of Sale Disclosure Package) so as to correct such statement or omission or effect such compliance.

(B) If at any time following the issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development the result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information contained in the Registration Statement or any Prospectus or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances prevailing at that subsequent time, not misleading, the Company has promptly notified or promptly will notify the Representative and has promptly amended or will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

(iv) The Company shall take or cause to be taken all necessary action to qualify the Shares for sale under the securities laws of such jurisdictions as the Representative reasonably designates and to continue such qualifications in effect so long as required for the distribution of the Shares, except that the Company shall not be required in connection therewith to qualify as a foreign corporation or as a dealer in securities in any jurisdiction in which it is not so qualified, to execute a general consent to service of process in any state or to subject itself to taxation in respect of doing business in any jurisdiction in which it is not otherwise subject.

(v) The Company will furnish to the Representative and counsel for the Representative copies of the Registration Statement, each Prospectus, any Issuer Free Writing Prospectus, and all amendments and supplements to such documents, in each case as soon as available and in such quantities as the Underwriters may from time to time reasonably request.

(vi) The Company will make generally available to its security holders as soon as practicable, but in any event not later than 15 months after the end of the Company’s current fiscal quarter, an earnings statement (which need not be audited) covering a 12-month period that shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158 of the Rules and Regulations.

(vii) (A) The Company, whether or not the transactions contemplated hereunder are consummated or this Agreement is terminated, will pay or cause to be paid (1) all expenses (including transfer taxes allocated to the respective transferees) incurred in connection with the delivery to the Underwriters of the Shares, (2) all expenses and fees (including, without limitation, fees and expenses of the Company’s counsel, but excluding fees and expenses of the Underwriters’ counsel) in connection with the preparation, printing, filing, delivery, and shipping of the Registration Statement (including the financial statements therein and all amendments, schedules, and exhibits thereto), the Shares, the Time of Sale Disclosure Package, the Prospectus, any Issuer Free Writing Prospectus and any amendment thereof or supplement thereto, (3) all reasonable filing fees and reasonable fees and disbursements of the Underwriters’ counsel incurred in connection with the qualification of the Shares for offering and sale by the Underwriters or by dealers under the securities or blue sky laws of the states and other jurisdictions that the Representative shall designate, (4) the fees and expenses of any transfer agent or registrar, (5) the reasonable filing fees and reasonable fees and disbursements of Underwriters’ counsel incident to any required review and approval by FINRA, of the terms of the sale of the Shares, (6) listing fees, if any, and (7) all other costs and expenses incident to the performance of the Company’s obligations hereunder that are not otherwise specifically provided for herein, provided, however, that the Underwriters shall not incur expenses pursuant to clauses (1) — (7) in excess of $25,000 without the written consent of the Company (all of the foregoing, the “ Company Expenses ”). The Company will also reimburse the Underwriters for all out-of-pocket accountable expenses (including, but not limited to, reasonable fees and disbursements of counsel, travel expenses, postage, facsimile and telephone charges) incurred by the Underwriters in connection with their investigation, preparing to market and marketing the Shares or in contemplation of performing their obligations hereunder. Notwithstanding anything contained herein, the maximum amount payable by the Company for the Underwriters’ counsel fees, disbursements and other out of pocket expenses pursuant to this Section 6(a)(vii)(A), exclusive of the expenses described in Section 6(a)(vii)(B) below and the Company Expenses, shall be $25,000.

(B) Contingent upon the consummation of the offering, on the Closing Date, the Company will (1) pay the Underwriters an amount equal to 1.5% of the gross proceeds received by the Company from the sale of the Underwritten Shares, the Secondary Shares and the Additional Shares, as applicable, as a non-accountable reimbursement of the Underwriters’ non-accountable expenses and (2) grant the Underwriters warrants, in the form attached hereto as Schedule IV , to purchase an amount of Common Stock equal to two percent (2.0%) of the aggregate number of shares sold pursuant to this Agreement.

(viii) The Company intends to apply the net proceeds from the sale of the Shares to be sold by it hereunder for the purposes set forth in the Time of Sale Disclosure Package and in the Final Prospectus.

(ix) The Company has not taken and will not take, directly or indirectly, during the Prospectus Delivery Period, any action designed to or that might reasonably be expected to cause or result in, or that has constituted, the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares.

(x) The Company represents and agrees that, unless it obtains the prior written consent of the Representative, and the Representative represents and agrees that, unless it obtains the prior written consent of the Company, it has not made and will not make any offer relating to the Shares that would constitute an Issuer Free Writing Prospectus; provided that the prior written consent of the parties hereto shall be deemed to have been given in respect of any free writing prospectus containing only the description of the transaction included in Schedule III . Any such free writing prospectus consented to by the Company and the Representative is hereinafter referred to as a “ Permitted Free Writing Prospectus .” The Company represents that it has treated or agrees that it will treat each Permitted Free Writing Prospectus as an “issuer free writing prospectus,” as defined in Rule 433, and has complied or will comply with the requirements of Rule 433 applicable to any Permitted Free Writing Prospectus, including timely Commission filing where required, legending and record-keeping.

(xi) The Company hereby agrees that, without the prior written consent of the Representative, it will not, during the period ending 90 days after the date hereof (“ Lock-Up Period ”), (i) offer, pledge, issue, sell, contract to sell, purchase, contract to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock; or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise; or (iii) file any registration statement with the Commission relating to the offering of any shares of Common Stock

or any securities convertible into or exercisable or exchangeable for Common Stock. The restrictions contained in the preceding sentence shall not apply to (1) the Shares to be sold hereunder, (2) the issuance of Common Stock upon the exercise of options or warrants or other convertible securities disclosed as outstanding in the Registration Statement (excluding exhibits thereto) or the Prospectus, or (3) the issuance of employee stock options not exercisable during the Lock-Up Period and the grant of restricted stock awards or restricted stock units (or the delivery of shares of Common Stock upon settlement thereof) pursuant to equity incentive plans described in the Registration Statement (excluding exhibits thereto) and the Prospectus. The restrictions contained in clause (iii) above shall not apply to any “Demand Registration” that may be requested on or after September 1, 2011 by “Qualified Investors,” as such terms are defined in the Registration Rights Agreement (“ Registration Rights Agreement ”) dated as of October 15, 2010, as amended, among the Company, CSI and the investor parties thereto. Notwithstanding the foregoing, if (x) the Company issues an earnings release or material news, or a material event relating to the Company occurs, during the last 17 days of the Lock-Up Period, or (y) prior to the expiration of the Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the Lock-Up Period, the restrictions imposed by this clause shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, unless the Representative waives such extension in writing.

(b) Each Selling Stockholder, severally and not jointly, covenants and agrees with the Underwriters as follows:

(i) The Selling Stockholders, whether or not the transactions contemplated hereunder are consummated or this Agreement is terminated, will pay or cause to be paid (A) all expenses (including transfer taxes allocated to the respective transferees) incurred in connection with the delivery to the Underwriters of the Secondary Shares to be sold by the Selling Stockholders hereunder.

(ii) The Selling Stockholders hereby agree that, without the prior written consent of the Representative, it will not, during the Lock-Up Period, (i) offer, pledge, issue, sell, contract to sell, purchase, contract to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock; or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. The restrictions contained in the preceding sentence shall not apply to (1) the Shares to be sold hereunder, (2) the issuance of Common Stock upon the exercise of options or warrants or other convertible securities disclosed as outstanding in the Registration Statement (excluding exhibits thereto) or the Prospectus, or (3) the issuance of employee stock options not exercisable during the Lock-Up Period and the grant of restricted stock awards or restricted stock units (or the delivery of shares of Common Stock upon settlement thereof)

pursuant to equity incentive plans described in the Registration Statement (excluding exhibits thereto) and the Prospectus. Notwithstanding the foregoing, if (x) the Company issues an earnings release or material news, or a material event relating to the Company occurs, during the last 17 days of the Lock-Up Period, or (y) prior to the expiration of the Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the Lock-Up Period, the restrictions imposed by this clause shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, unless the Representative waives such extension in writing. The restrictions contained in this subsection shall not apply to any “Demand Registration” that may be requested on or after September 1, 2011 by the Selling Stockholders; provided however that nothing in this provision enables the sale of any shares of Common Stock by the Selling Stockholders prior to the expiration of the Lock-Up Period.

(iii) Such Selling Stockholder will deliver to the Underwriters prior to the applicable Closing Date a properly completed and executed United States Treasury Department Form W-9.

(iv) During the Prospectus Delivery Period, such Selling Stockholder will advise the Representative promptly, and if requested by the Representative, will confirm such advice in writing, of any change in information relating to such Selling Stockholder in the Registration Statement, the Time of Sale Disclosure Package or any Prospectus.

(v) Such Selling Stockholder agrees that it will not prepare or have prepared on its behalf or use or refer to any “free writing prospectus” (as such term is defined in Rule 405 under the Act), and agrees that it will not distribute any written materials in connection with the offer or sale of the Shares.

7. Conditions of the Underwriters’ Obligations. The obligations of the Underwriters hereunder to purchase the Shares are subject to the accuracy, as of the date hereof and at the Closing Date (as if made at the Closing Date), of and compliance with all representations, warranties and agreements of the Company and the Selling Stockholders contained herein, the performance by the Company and the Selling Stockholders of their respective obligations hereunder and the following additional conditions:

(a) If filing of the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, is required under the Securities Act or the Rules and Regulations, the Company shall have filed the Prospectus (or such amendment or supplement) or such Issuer Free Writing Prospectus with the Commission in the manner and within the time period so required (without reliance on Rule 424(b)(8) or 164(b) under the Securities Act); the Registration Statement shall remain effective; no stop order suspending the effectiveness of the Registration Statement or any part thereof, any Rule 462 Registration Statement, or any amendment thereof, nor suspending or preventing the use of the Time of Sale Disclosure Package, the Prospectus or any Issuer Free Writing Prospectus shall have been issued; no proceedings for the issuance of such an order shall have been initiated or threatened; any request of the Commission or the Representative for additional information (to be included in the Registration Statement, the Time of Sale Disclosure Package, the Prospectus, any Issuer Free Writing Prospectus or otherwise) shall have been complied with to the Representative’s satisfaction.

(b) The Shares shall be qualified for listing on The NASDAQ Capital Market.

(c) FINRA shall have raised no objection to the fairness and reasonableness of the underwriting terms and arrangements.

(d) The Representative shall not have reasonably determined, and advised the Company, that the Registration Statement, the Time of Sale Disclosure Package or the Prospectus, or any amendment thereof or supplement thereto, or any Issuer Free Writing Prospectus, contains an untrue statement of fact that, in the Representative’s reasonable opinion, is material, or omits to state a fact that, in the Representative’s reasonable opinion, is material and is required to be stated therein or necessary to make the statements therein not misleading.

(e) On the Closing Date, there shall have been furnished to the Representative the opinion and negative assurance letters of Reed Smith LLP, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representative, to the effect set forth in Schedule V .

(f) On the Closing Date, there shall have been furnished to the Representative the opinion of legal counsel to each of the Selling Stockholders, dated the Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representative, to the effect set forth in Schedule VI.

(g) The Representative shall have received a letter of KPMG LLP, on the date hereof and on the Closing Date addressed to the Underwriters, confirming that they are independent public accountants within the meaning of the Securities Act and are in compliance with the applicable requirements relating to the qualifications of accountants under Rule 2-01 of Regulation S-X of the Commission, and confirming, as of the date of each such letter (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Time of Sale Disclosure Package, as of a date not prior to the date hereof or more than five days prior to the date of such letter), the conclusions and findings of said firm with respect to the financial information and other matters required by the Representative.

(h) On the Closing Date, there shall have been furnished to the Representative a certificate, dated the Closing Date and addressed to the Underwriters, signed by the chief executive officer and the chief financial officer of the Company, in their capacity as officers of the Company, to the effect that:

(i) The representations and warranties of the Company in this Agreement that are qualified by materiality or by reference to any Material Adverse Effect are true and correct in all respects, and all other representations and warranties of the Company in this Agreement are true and correct, in all material respects, as if made at and as of the Closing Date, and the Company has complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied at or prior to the Closing Date;

(ii) No stop order or other order (A) suspending the effectiveness of the Registration Statement or any part thereof or any amendment thereof, (B) suspending the qualification of the Shares for offering or sale, or (C) suspending or preventing the use of the Time of Sale Disclosure Package, the Prospectus or any Issuer Free Writing Prospectus, has been issued, and no proceeding for that purpose has been instituted or, to their knowledge, is contemplated by the Commission or any state or regulatory body; and

(iii) There has been no occurrence of any event resulting or reasonably likely to result in a Material Adverse Effect during the period from and after the date of this Agreement and prior to the Closing Date.

(i) On the Closing Date, there shall been furnished to the Representative a certificate, in form and substance reasonably satisfactory to the Representative, dated the Closing Date and addressed to the Underwriters, signed by the chief financial officer of the Company, to the effect that certain financial information attached to the certificate is accurate in all material respects as of the date thereof and as of the date of the Time of Sale Disclosure Package.

(j) On the Closing Date, there shall have been furnished to the Representative a certificate, dated the Closing Date and addressed to the Underwriters, signed by each Selling Stockholder, to the effect that the representations and warranties of such Selling Stockholder in this Agreement are true and correct, in all material respects, as if made at and as of the Closing Date, and that such Selling Stockholder has complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied at or prior to the Closing Date.

(k) On or before the date hereof, the Representative shall have received duly executed “lock-up” agreements, in a form acceptable to the Representative, between the Representative and the persons set forth on Schedule VII .

(l) The Company and the Selling Stockholders shall have furnished to the Representative and its counsel such additional documents, certificates and evidence as the Representative or its counsel may have reasonably requested.

If any condition specified in this Section 7 shall not have been fulfilled when and as required to be fulfilled, this Agreement may be terminated by the Representative by notice to the Company and the Selling Stockholders at any time at or prior to the Closing Date and such termination shall be without liability of any party to any other party, except that Section 6(a)(vii), Section 8 and Section 9 shall survive any such termination and remain in full force and effect.

8. Indemnification and Contribution .

(a) The Company agrees to indemnify, defend and hold harmless each Underwriter, its affiliates, directors, officers and employees, and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any losses, claims, damages or liabilities to which such Underwriter or such person may become subject, under the Securities Act or otherwise (including in settlement of any litigation if such settlement is effected with the written consent of the Company), insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, including the information deemed to be a part of the Registration Statement at the time of effectiveness and at any subsequent time pursuant to Rules 430A and 430B of the Rules and Regulations, or arise out of or are based upon the omission from the Registration Statement, or alleged omission to state therein, a material fact required to be stated therein or necessary to make the statements therein not misleading, (ii) an untrue statement or alleged untrue statement of a material fact contained in the Time of Sale Disclosure Package, the Prospectus, or any amendment or supplement thereto (including any documents filed under the Exchange Act and deemed to be incorporated by reference into the Registration Statement or the Prospectus), any Issuer Free Writing Prospectus, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, or (iii) in whole or in part, any failure of the Company to perform its obligations hereunder or under law, and will reimburse the Underwriters for any legal or other expenses reasonably incurred by them in connection with investigating or defending against such loss, claim, damage, liability or action; provided, however , that the Company shall not be liable in any such case to the extent that any such loss, claim, damage, liability or action arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in the Registration Statement, the Time of Sale Disclosure Package, the Prospectus, or any amendment or supplement thereto or any Issuer Free Writing Prospectus, in reliance upon and in conformity with written information furnished to the Company by the Representative specifically for use in the preparation thereof, which written information is described in Section 8(g).

(b) Each Selling Stockholder will, severally and not jointly, indemnify, defend and hold harmless each Underwriter against any losses, claims, damages or liabilities, joint or several, to which such Underwriter may become subject, under the Securities Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, the Prospectus or any Issuer Free Writing Prospectus, or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, but only with reference to the information relating to such Selling Stockholder furnished by such Selling Stockholder to the Company for use therein which shall consist of the statements set forth under the caption “Principal and Selling Stockholders” in the Time of Sale Disclosure Package and any Prospectus. The liability of each Selling Stockholder under the indemnity agreement contained in this Section 8(b) shall be limited to an amount equal to the proceeds (net of underwriting discounts and concessions, but before deducting other expenses) received by the Selling Stockholder from the sale of the Shares sold by such Selling Stockholder under this Agreement.

(c) Each Underwriter will, severally and not jointly, indemnify, defend and hold harmless the Company and the Selling Stockholders, their respective affiliates, directors, officers and employees, and each person, if any, who controls the Company or a Selling Stockholder within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any losses, claims, damages or liabilities to which the Company or a Selling Stockholder may become subject, under the Securities Act or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of such Underwriter), insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or arise out of or are based upon any omission from the Registration Statement, or alleged omission to state therein, a material fact required to be stated therein or necessary in order to make the statements therein not misleading or (ii) an untrue statement or alleged untrue statement of a material fact contained in the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or the Time of Sale Disclosure Package, or arise out of or are based upon any omission or alleged omission to state therein a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Registration Statement, the Time of Sale Disclosure Package, the Prospectus, or any amendment or supplement, or any Issuer Free Writing Prospectus in reliance upon and in conformity with written information furnished to the Company by the Representative specifically for use in the preparation thereof, and will reimburse the Company or a Selling Stockholder for any legal or other expenses reasonably incurred by the Company or a Selling Stockholder in connection with investigating or defending against any such loss, claim, damage, liability or action.

(d) Promptly after receipt by an indemnified party under subsection (a) or (b) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement thereof; but the failure to notify the indemnifying party shall not relieve the indemnifying party from any liability that it may have to any indemnified party except to the extent such indemnifying party has been materially prejudiced by such failure. In case any such action shall be brought against any indemnified party, and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate in, and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party, and after notice from the indemnifying party to such indemnified party of the indemnifying party’s election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof; provided , however , that if (i) the indemnified party has reasonably concluded (based on advice of counsel) that there may be legal defenses available to it or other indemnified parties that are different from or in addition to those available to the indemnifying party, (ii) a conflict or potential conflict exists (based on advice of counsel to the indemnified party) between the indemnified party and the indemnifying party (in which case the indemnifying party will not have the right to direct the defense of such action on behalf of the indemnified party), or (iii) the indemnifying party has not in fact employed counsel reasonably satisfactory to the indemnified party to assume the defense of such action within a reasonable time after receiving notice of the commencement of the action, the indemnified party shall have the right to employ a single counsel to represent it in any claim in respect of which indemnity may be sought under subsection (a) or (b) of this Section 8, in which event the reasonable fees and expenses of such separate counsel shall be borne by the indemnifying party or parties and reimbursed to the indemnified party as incurred.

The indemnifying party under this Section 8 shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party against any loss, claim, damage, liability or expense by reason of such settlement or judgment. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is a party or could be named and indemnity was or would be sought hereunder by such indemnified party, unless such settlement, compromise or consent (a) includes an unconditional release of such indemnified party from all liability for claims that are the subject matter of such action, suit or proceeding and (b) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

(e) If the indemnification provided for in this Section 8 is unavailable or insufficient to hold harmless an indemnified party under subsection (a) or (b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in subsection (a) or (b) above, (i) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other from the offering and sale of the Shares or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company and the Selling Stockholders on the one hand and the Underwriters on the other in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company and the Selling Stockholders bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Final Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company, the Selling Stockholders or the Underwriters and the parties’ relevant intent, knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The Company, the Selling Stockholders and the Underwriters agree that it would not be just and equitable if contributions pursuant to this subsection (e) were to be determined by pro rata allocation or by any other method of allocation that does not take account of the equitable considerations referred to in the first sentence of this subsection (e). The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this subsection (e) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending against any action or claim that is the subject of this subsection (e). Notwithstanding the provisions of this subsection (e), the Underwriters shall not be required to

contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages that the Underwriters have otherwise been required to pay by reason of such untrue statement or omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 8 are several and not joint, in proportion to their respective underwriting commitments as set forth opposite their respective names on Schedule I . For purposes of this Section 8, each officer and employee of an Underwriter and each person, if any, who controls an Underwriter within the meaning of the Securities Act or the Exchange Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company with the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as the Company.

(f) The obligations of the Company and the Selling Stockholders under this Section 8 shall be in addition to any liability that the Company and the Selling Stockholders may otherwise have and the benefits of such obligations shall extend, upon the same terms and conditions, to each person, if any, who controls the Underwriters within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act; and the obligations of the Underwriters under this Section 8 shall be in addition to any liability that the Underwriters may otherwise have and the benefits of such obligations shall extend, upon the same terms and conditions, to the Company, the Selling Stockholders and their respective officers, directors and each person who controls the Company or a Selling Stockholder within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act.

(g) For purposes of this Agreement, the Representative confirms, and the Company and the Selling Stockholders acknowledge, that there is no information concerning the Underwriters furnished in writing to the Company and the Selling Stockholders by the Representative specifically for preparation of or inclusion in the Registration Statement, the Time of Sale Disclosure Package or the Prospectus or any Issuer Free Writing Prospectus, other than the statements set forth in the last paragraph on the cover page of the Prospectus and the statements set forth in the “Underwriting” section of the Prospectus and Time of Sale Disclosure Package, only insofar as such statements relate to the amount of selling concession and re-allowance or to over-allotment and related activities that may be undertaken by the Underwriters.

9. Representations and Agreements to Survive Delivery . All representations, warranties, and agreements of the Company and the Selling Stockholders herein or in certificates delivered pursuant hereto, including, but not limited to, the agreements of the Underwriters, the Selling Stockholders and the Company contained in Section 6(a)(vii) and Section 8 hereof, shall remain operative and in full force and effect regardless of any investigation made by or on behalf of the Underwriters or any controlling person thereof, or the Company and the Selling Stockholders or any of their respective officers, directors, or controlling persons, and shall survive delivery of, and payment for, the Shares to and by the Underwriters hereunder.

10. Termination of this Agreement .

(a) The Representative shall have the right to terminate this Agreement by giving notice to the Company and the Selling Stockholders as hereinafter specified at any time at or prior to the Closing Date, if in the discretion of the Representative, (i) there has occurred any event, act or occurrence that has materially disrupted, or in the opinion of the Representative, will in the future materially disrupt, the securities markets or there shall be such a material adverse change in general financial, political or economic conditions or the effect of international conditions on the financial markets in the United States is such as to make it, in the judgment of the Representative, inadvisable or impracticable to market the Shares or enforce contracts for the sale of the Shares (ii) trading in the Company’s Common Stock shall have been suspended by the Commission or The NASDAQ Capital Market or trading in securities generally on the Nasdaq Global Market, New York Stock Exchange or NYSE Amex shall have been suspended, (iii) minimum or maximum prices for trading shall have been fixed, or maximum ranges for prices for securities shall have been required, on the Nasdaq Global Market, New York Stock Exchange or NYSE Amex, by such exchange or by order of the Commission or any other governmental authority having jurisdiction, (iv) a banking moratorium shall have been declared by federal or state authorities, (v) there shall have occurred any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States, any declaration by the United States of a national emergency or war, any substantial change or development involving a prospective substantial change in United States or international political, financial or economic conditions or any other calamity or crisis, (vi) the Company suffers any loss by strike, fire, flood, earthquake, accident or other calamity, whether or not covered by insurance, or (vii) in the judgment of the Representative, there has been, since the time of execution of this Agreement or since the respective dates as of which information is given in the Prospectus, any material adverse change in the assets, properties, condition, financial or otherwise, or in the results of operations, business affairs or business prospects of the Company and its subsidiaries considered as a whole, whether or not arising in the ordinary course of business. Any such termination shall be without liability of any party to any other party except that the provisions of Section 6(a)(vii) and Section 8 hereof shall at all times be effective and shall survive such termination.

(b) If the Representative elects to terminate this Agreement as provided in this Section, the Company and the Selling Stockholders shall be notified promptly by the Representative by telephone, confirmed by letter.

11. Notices . Except as otherwise provided herein, all communications hereunder shall be in writing and, if to the Representative, shall be mailed, delivered or telecopied to Roth Capital Partners, LLC, 24 Corporate Plaza, Newport Beach, CA 92660, telecopy number: (949) 720-7227, Attention: Managing Director; if to the Company, shall be mailed, delivered or telecopied to it at Clean Diesel Technologies, Inc., 4567 Telephone Road, Suite 206, Ventura, CA 93033, telecopy number: (805) 639-9466, Attention: Chief Financial Officer; and if to the Selling Stockholders, shall be mailed, delivered or telecopied to them at 160 Federal Street, 18 ^th Floor, Boston, MA 02110-1700, telecopy number: (617) 912-1449, Attention: Janet James; or in each case to such other address as the person to be notified may have requested in writing. Any party to this Agreement may change such address for notices by sending to the parties to this Agreement written notice of a new address for such purpose.

12. Persons Entitled to Benefit of Agreement . This Agreement shall inure to the benefit of and be binding upon the parties hereto and their respective successors and assigns and the controlling persons, officers and directors referred to in Section 8. Nothing in this Agreement is intended or shall be construed to give to any other person, firm or corporation any legal or equitable remedy or claim under or in respect of this Agreement or any provision herein contained. The term “successors and assigns” as herein used shall not include any purchaser, as such purchaser, of any of the Shares from the Underwriters.

13. Absence of Fiduciary Relationship . The Company and each of the Selling Stockholders acknowledge and agree that: (a) the Underwriters have been retained solely to act as underwriters in connection with the sale of the Shares and that no fiduciary, advisory or agency relationship between the Company and the Selling Stockholders and the Underwriters have been created in respect of any of the transactions contemplated by this Agreement, irrespective of whether the Underwriters have advised or are advising the Company or the Selling Stockholders on other matters; (b) the price and other terms of the Shares set forth in this Agreement were established by the Company and the Selling Stockholders following discussions and arms-length negotiations with the Underwriters and the Company and the Selling Stockholders are capable of evaluating and understanding and understand and accept the terms, risks and conditions of the transactions contemplated by this Agreement; (c) they have been advised that the Underwriters and their respective affiliates are engaged in a broad range of transactions that may involve interests that differ from those of the Company and the Selling Stockholders and that the Underwriters have no obligation to disclose such interest and transactions to the Company or the Selling Stockholders by virtue of any fiduciary, advisory or agency relationship; (d) they have been advised that the Underwriters are acting, in respect of the transactions contemplated by this Agreement, solely for the benefit of the Underwriters, and not on behalf of the Company or the Selling Stockholders.

14. Amendments and Waivers . No supplement, modification or waiver of this Agreement shall be binding unless executed in writing by the party to be bound thereby. The failure of a party to exercise any right or remedy shall not be deemed or constitute a waiver of such right or remedy in the future. No waiver of any of the provisions of this Agreement shall be deemed or shall constitute a waiver of any other provision hereof (regardless of whether similar), nor shall any such waiver be deemed or constitute a continuing waiver unless otherwise expressly provided.

15. Partial Unenforceability . The invalidity or unenforceability of any section, paragraph, clause or provision of this Agreement shall not affect the validity or enforceability of any other section, paragraph, clause or provision.

16. Governing Law . This Agreement shall be governed by and construed in accordance with the laws of the State of New York.

17. Submission to Jurisdiction . The Company and each Selling Stockholder irrevocably (a) submit to the jurisdiction of any court of the State of New York for the purpose of any suit, action, or other proceeding arising out of this Agreement, or any of the agreements or transactions contemplated by this Agreement, the Registration Statement and the Prospectus (each a “Proceeding”), (b) agree that all claims in respect of any Proceeding may be heard and determined in any such court, (c) waive, to the fullest extent permitted by law, any immunity from jurisdiction of any such court or from any legal process therein, (d) agree not to commence any Proceeding other than in such courts, and (e) waive, to the fullest extent permitted by law, any claim that such Proceeding is brought in an inconvenient forum. THE COMPANY (ON BEHALF OF ITSELF AND, TO THE FULLEST EXTENT PERMITTED BY LAW, ON BEHALF OF ITS RESPECTIVE EQUITY HOLDERS AND CREDITORS) AND THE SELLING STOCKHOLDERS HEREBY WAIVE ANY RIGHT THEY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY CLAIM BASED UPON, ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT AND THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT, THE REGISTRATION STATEMENT, AND THE PROSPECTUS.

18. Counterparts. This Agreement may be executed in one or more counterparts and, if executed in more than one counterpart, the executed counterparts shall each be deemed to be an original and all such counterparts shall together constitute one and the same instrument.

Please sign and return to the Company the enclosed duplicates of this letter whereupon this letter will become a binding agreement between the Company, the Selling Stockholders and the Underwriters in accordance with its terms.

Confirmed as of the date first above-mentioned by the Underwriters.
ROTH CAPITAL PARTNERS, LLC Acting as Representative of the Underwriters named in Schedule I
By:		/s/ Aaron M. Gurewitz   Name: Aaron M. Gurewitz
		Title:   Head of Equity Markets

[Signature page to Underwriting Agreement]

SCHEDULE I

Number of

Number of

Underwritten

Secondary

Number of

Shares to be

Shares to be

Additional Shares

Purchased

Purchased

to be Purchased

Underwriters

Roth Capital Partners, LLC

2,512,750

76,000

388,313

Maxim Group LLC

132,250

4,000

20,437

Total

2,645,000

80,000

408,750

SCHEDULE II

		Number of
		Underwritten and				Number of
		Secondary Shares				Additional Shares
		to be Sold				to be Sold
Company:
Clean Diesel Technologies, Inc.			2,645,000				408,750
Selling Stockholders:
RockPort Capital Partners, L.P.			72,800				—
RP Co-Investment Fund I, L.P.			7,200				—
Total			2,725,000				408,750

Entities affiliated with Special Situations Fund have indicated an interest in purchasing up to 2,200,000 shares in the offering. Assuming completion of the offering, they will own approximately 33% of the Company’s total outstanding shares (assuming no exercise of the over-allotment option).

SCHEDULE IV

Warrant

SCHEDULE V

Company Opinions

SCHEDULE VI

Selling Stockholders Opinions

SCHEDULE VII

Lockups