COMBIMATRIX CORPORATION WARRANT TO PURCHASE COMMON STOCK

3.             COVENANTS OF THE COMPANY

3.1          Covenants as to Warrant Shares.  The Company covenants and agrees that all Warrant Shares that may be issued upon the exercise of the rights represented by this Warrant will, upon issuance in accordance with the terms hereof, be validly issued and outstanding, fully paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof (other than restrictions pursuant to securities laws).  The Company further covenants and agrees that the Company will, at all times during the Exercise Period, have authorized and reserved, free from preemptive rights, a sufficient number of shares of Common Stock to provide for the exercise of the rights represented by this Warrant.  If at any time during the Exercise Period the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock to such number of shares as shall be sufficient for such purposes.

3.2          No Impairment.  Except and to the extent as waived or consented to by the Holder, the Company will not, by amendment of its Certificate of Incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, directly or indirectly avoid or seek to avoid the observance or performance of any of the terms to be observed or performed hereunder by the Company, but will at all times in good faith assist in the carrying out of all the provisions of this Warrant and in the taking of all such action as may be necessary or appropriate in order to protect the exercise rights of the Holder against impairment.

4.             ADJUSTMENT OF EXERCISE PRICE AND SHARES.

4.1          In the event of changes in the outstanding Common Stock of the Company by reason of stock dividends, split-ups, recapitalizations, reclassifications, combinations or exchanges of shares, separations, reorganizations, liquidations, consolidation, acquisition of the Company (whether through merger or acquisition of substantially all the assets or stock of the Company), or the like, the number, class and type of shares available under the Warrant in the aggregate and the Exercise Price shall be correspondingly adjusted to give the Holder of the Warrant, on exercise for the same aggregate Exercise Price, the total number, class, and type of shares or other property as the Holder would have owned had the Warrant been exercised prior to the event and had the Holder continued to hold such shares until the event requiring adjustment.  The form of this Warrant need not be changed because of any adjustment in the number of Warrant Shares subject to this Warrant.

4.2          If at any time or from time to time the holders of Common Stock of the Company (or any shares of stock or other securities at the time receivable upon the exercise of this Warrant) shall have received or become entitled to receive on a pro rata basis, without payment therefor,

4

(i)            Common Stock or any shares of stock or other securities which are at any time directly or indirectly convertible into or exchangeable for Common Stock, or any rights or options to subscribe for, purchase or otherwise acquire any of the foregoing by way of dividend or other distribution (other than a dividend or distribution covered in Section 4.1 above),

(ii)           any cash paid or payable otherwise than as a cash dividend; or

(iii)         Common Stock or additional stock or other securities or property (including cash) by way of spinoff, split-up, reclassification, combination of shares or similar corporate rearrangement (other than shares of Common Stock pursuant to Section 4.1 above), then and in each such case, the Holder hereof will, upon the exercise of this Warrant, be entitled to receive, in addition to the number of shares of Common Stock receivable thereupon, and without payment of any additional consideration therefor, the amount of stock and other securities and property which such Holder would hold on the date of such exercise had such Holder been the holder of record of such Common Stock as of the date on which holders of Common Stock received or became entitled to receive such shares or all other additional stock and other securities and property.

4.3          Upon the occurrence of each adjustment pursuant to Section 4.1 or 4.2, the Company at its expense will promptly compute such adjustment in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in reasonable detail the facts upon which such adjustment is based.  Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Company’s transfer agent.

5.             FRACTIONAL SHARES.  No fractional shares shall be issued upon the exercise of this Warrant.  All Warrant Shares (including fractions) issuable upon exercise of this Warrant may be aggregated for purposes of determining whether the exercise would result in the issuance of any fractional share.  If, after aggregation, the exercise would result in the issuance of a fractional share, the Company will in lieu of issuance of any fractional share, pay the Holder otherwise entitled to such fraction a sum in cash equal to the product resulting from multiplying the then current fair market value of a Warrant Share by such fraction, rounded down to the nearest whole cent.

6.             FUNDAMENTAL TRANSACTIONS.  If, at any time while this Warrant is outstanding, (i) the Company effects any merger of the Company with or into another entity, (ii) the Company effects any sale of all or substantially all of its assets in one or a series of related transactions, (iii) any tender offer or exchange offer (whether by the Company or another individual or entity, other than employee stock option exchange offers) is completed pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property or (iv) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (other than as a result of a subdivision or combination of shares of Common Stock covered by Section 4 above) (in any such case, a “Fundamental Transaction”), then, upon any subsequent exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have been issuable upon such exercise immediately prior to the occurrence of such Fundamental Transaction without regard to the limitations on exercise contained in Section 2.4 herein if the Company is not the surviving entity in such Fundamental Transaction, the number of shares of Common Stock of the successor or acquiring corporation or of the Company, if it is the surviving corporation, and any additional consideration (the “Alternate Consideration”) receivable upon or as a result of such reorganization, reclassification, merger, consolidation or disposition of assets by a Holder of the number of shares of Common Stock for which this Warrant is exercisable immediately prior to such event without regard to the limitations on exercise contained in Section 2.4 herein if the Company is not the surviving entity in such Fundamental Transaction.