Document:

Form of Warrant Certificate

    Exhibit
      4.1

    

    WA- 

     

     

    ACACIA
      RESEARCH CORPORATION 

     

    WARRANT
      TO PURCHASE COMMON STOCK

     

    May
      4, 2007

     

    Void
      After May 3, 2012

     

    THIS
      CERTIFIES THAT,
      for
      value received,  ,
      or
      permitted registered assigns (the “Holder”),
      is
      entitled to subscribe for and purchase at the Exercise Price (defined below)
      from Acacia
      Research Corporation,
      a
      Delaware corporation (the
      “Company”),
      up to
  shares
      of
      the Company’s Acacia Research-CombiMatrix common stock, par value $0.001 per
      share (the “Common
      Stock”).

     

    1.     DEFINITIONS.
      As
      used
      herein, the following terms shall have the following respective
      meanings:

     

    (a) “Exercise
      Period” shall mean the period commencing on the date hereof and ending five (5)
      years from the date hereof, unless sooner terminated as provided
      below.

     

    (b) “Exercise
      Price” shall mean $0.55 per share, subject to adjustment pursuant to
      Section 5 below.

     

    (c) “Exercise
      Shares” shall mean the shares of Common Stock issuable upon exercise of this
      Warrant.

     

    (d) “Trading
      Day” shall mean
      (a)
      any day on which the Common Stock is listed or quoted and traded on its primary
      Trading Market, (b) if the Common Stock is not then listed or quoted and traded
      on any Eligible Market, then a day on which trading occurs on the OTC
      Bulletin Board
      (or any
      successor thereto), or (c) if trading does not occur on the OTC Bulletin Board
      (or any successor thereto), any Business Day.

    

    2.     EXERCISE
      OF WARRANT.  The
      rights represented by this Warrant may be exercised in whole or in part at
      any
      time during the Exercise Period, by delivery of the following to the Company
      at
      its address set forth on the signature page hereto (or at such other address
      as
      it may designate by notice in writing to the Holder):

     

    (a) An
      executed Notice of Exercise in the form attached hereto;

    

    
      
         

      

      
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    (b) Payment
      of the Exercise Price either (i) in cash or by check, (ii) by cancellation
      of
      indebtedness, or (iii) pursuant to Section 2.1 below; and

     

    (c) This
      Warrant.

     

    The
      Holder shall not be required to deliver the original Warrant in order to effect
      the exercise hereunder. Execution and delivery of the Notice of Exercise shall
      have the same effect as cancellation of the original Warrant and issuance of
      a
      new Warrant evidencing the right to purchase the remaining number of Exercise
      Shares.

    

    Certificates
      for shares purchased hereunder shall be transmitted by the transfer agent of
      the
      Company to the Holder by crediting the account of the Holder’s prime broker with
      the  Depository Trust Company through its Deposit Withdrawal Agent
      Commission system if the Company is a participant in such system, and otherwise
      by physical delivery to the address specified by the Holder in the Notice of
      Exercise within three business days from the delivery to the Company of the
      Notice of Exercise, surrender of this Warrant and payment of the aggregate
      Exercise Price as set forth above.  This Warrant shall be deemed to have
      been exercised on the date the Exercise Price is received by the Company. 
The Exercise Shares shall be deemed to have been issued, and Holder or any
      other
      person so designated to be named therein shall be deemed to have become a holder
      of record of such shares for all purposes, as of the date the Warrant has been
      exercised by payment to the Company of the Exercise Price.

     

    In
      addition to any other rights available to the Holder, if the Company fails
      to
      deliver to the Holder a certificate representing Exercise Shares by the third
      Trading Day after the date on which delivery of such certificate is required
      by
      this Warrant, and if after such third Trading Day the Holder purchases (in
      an
      open market transaction or otherwise) shares of Common Stock to deliver in
      satisfaction of a sale by the Holder of the Warrant Shares that the Holder
      anticipated receiving from the Company (a “Buy-In”),
      then
      in the Holder’s sole discretion, the Company shall within three Trading Days
      after the Holder’s request, either (i) pay cash to the Holder in an amount equal
      to the Holder’s total purchase price (including brokerage commissions, if any)
      for the shares of Common Stock so purchased less the Exercise Price (the
“Buy-In
      Price”),
      at
      which point the Company’s obligation to deliver such certificate (and to issue
      such Common Stock) shall terminate, or (ii) promptly honor its obligation to
      deliver to the Holder a certificate or certificates representing such Common
      Stock and pay cash to the Holder in an amount equal to the excess (if any)
      of
      the Buy-In Price over the product of (A) such number of shares of Common Stock,
      times (B) the Closing Price on the date of the event giving rise to the
      Company’s obligation to deliver such certificate.

     

    The
      person in whose name any certificate or certificates for Exercise Shares are
      to
      be issued upon exercise of this Warrant shall be deemed to have become the
      holder of record of such shares on the date on which this Warrant was
      surrendered and payment of the Exercise Price was made, irrespective of the
      date
      of delivery of such certificate or certificates, except that, if the date of
      such surrender and payment is a date when the stock transfer books of the
      Company are closed, such person shall be deemed to have become the holder of
      such shares at the close of business on the next succeeding date on which the
      stock transfer books are open.

    

    
      
         

      

      
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    To
      the
      extent permitted by law, the Company’s obligations to issue and deliver Exercise
      Shares in accordance with the terms hereof are absolute and unconditional,
      irrespective of any action or inaction by the Holder to enforce the same, any
      waiver or consent with respect to any provision hereof, the recovery of any
      judgment against any person or entity or any action to enforce the same, or
      any
      setoff, counterclaim, recoupment, limitation or termination, or any breach
      or
      alleged breach by the Holder or any other person or entity of any obligation
      to
      the Company or any violation or alleged violation of law by the Holder or any
      other person or entity, and irrespective of any other circumstance which might
      otherwise limit such obligation of the Company to the Holder in connection
      with
      the issuance of Exercise Shares. Nothing herein shall limit a Holder’s right to
      pursue any other remedies available to it hereunder, at law or in equity
      including, without limitation, a decree of specific performance and/or
      injunctive relief with respect to the Company’s failure to timely deliver
      certificates representing shares of Common Stock upon exercise of the Warrant
      as
      required pursuant to the terms hereof. 

    

    This
      Warrant shall be non-callable.

    

    2.1.     Net
      Exercise. 
If
      during the Exercise Period, the fair market value of one share of the Common
      Stock is greater than the Exercise Price (at the date of calculation as set
      forth below), in lieu of exercising this Warrant by payment of cash or by check,
      or by cancellation of indebtedness, the Holder may elect to receive shares
      equal
      to the value (as determined below) of this Warrant (or the portion thereof
      being
      canceled) by surrender of this Warrant at the principal office of the Company
      together with the properly endorsed Notice of Exercise in which event the
      Company shall issue to the Holder a number of shares of Common Stock computed
      using the following formula:

     

    X
      =
Y
      (A-B)

    A

     

    Where
      X =
      the number of shares of Common Stock to be issued to the Holder

    

    
      	Y
              =	
              the
                number of shares of Common Stock purchasable under the Warrant or,
                if only
                a portion of the Warrant is being exercised, the portion of the Warrant
                being canceled (at the date of such
                calculation)

            

    

      

    
      	
              A
                =
                

            	
              the
                fair market value of one share of the Company’s Common Stock (at the date
                of such calculation)

            

    

     

    
      	
               B
                = 

            	
              Exercise
                Price (as adjusted to the date of such
                calculation)

            

    

     

    For
      purposes of the above calculation, the “fair market value” of one share of
      Common Stock shall mean (i) the average of the closing sales prices for the
      shares of Common Stock on the Nasdaq Global Market or other trading market
      where
      such security is listed or traded as reported by Bloomberg Financial Markets
      (or
      a comparable reporting service of national reputation selected by the Company
      and reasonably acceptable to the Holder if Bloomberg Financial Markets is not
      then reporting sales prices of such security) (collectively, “Bloomberg”) for
      the 10 consecutive trading days immediately preceding such date, or (ii) if
      the
      Nasdaq Global Market is not the principal trading market for the shares of
      Common Stock, the average of the reported sales prices reported by Bloomberg
      on
      the principal trading market for the Common Stock during the same period, or,
      if
      there is no sales price for such period, the last sales price reported by
      Bloomberg for such period, or (iii) if neither of the foregoing applies, the
      last sales price of such security in the over-the-counter market on the pink
      sheets or bulletin board for such security as reported by Bloomberg, or if
      no
      sales price is so reported for such security, the last bid price of such
      security as reported by Bloomberg or (iv) if fair market value cannot be
      calculated as of such date on any of the foregoing bases, the fair market value
      shall be as determined by the Board of Directors of the Company in the exercise
      of its good faith judgment. 

     

    
      
         

      

      
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    2.2.     Issuance
      of New Warrants. 
      Upon any partial exercise of this Warrant, the Company, at its expense, will
      forthwith and, in any event within five business days, issue and deliver to
      the
      Holder a new warrant or warrants of like tenor, registered in the name of the
      Holder, exercisable, in the aggregate, for the balance of the number of shares
      of Common Stock remaining available for purchase under the Warrant.

     

    2.3.     Payment
      of Taxes and Expenses. 
      The Company shall pay any recording, filing, stamp or similar tax which may
      be
      payable in respect of any transfer involved in the issuance of, and the
      preparation and delivery of certificates (if applicable) representing, (i)
      any
      Exercise Shares purchased upon exercise of this Warrant and/or (ii) new or
      replacement warrants in the Holder’s name or the name of any transferee of all
      or any portion of this Warrant.

    

    2.4.     Exercise
      Limitations; Holder’s Restrictions.
      A
      Holder shall not have the right to exercise any portion of this Warrant,
      pursuant to Section 2 or otherwise, to the extent that after giving effect
      to
      such issuance after exercise, such Holder (together with such Holder’s
      affiliates), as set forth on the applicable Notice of Exercise, would
      beneficially own in excess of 4.99% of the number of shares of the Common Stock
      outstanding immediately after giving effect to such issuance. For purposes
      of
      the foregoing sentence, the number of shares of Common Stock beneficially owned
      by such Holder and its affiliates shall include the number of shares of Common
      Stock issuable upon exercise of this Warrant with respect to which the
      determination of such sentence is being made, but shall exclude the number
      of
      shares of Common Stock which would be issuable upon (A) exercise of the
      remaining, nonexercised portion of this Warrant beneficially owned by such
      Holder or any of its affiliates and (B) exercise or conversion of the
      unexercised or nonconverted portion of any other securities of the Company
      (including, without limitation, any other shares of Common Stock or Warrants)
      subject to a limitation on conversion or exercise analogous to the limitation
      contained herein beneficially owned by such Holder or any of its affiliates.
      Except as set forth in the preceding sentence, for purposes of this Section
      2.4,
      beneficial ownership shall be calculated in accordance with Section 13(d) of
      the
      Exchange Act, it being acknowledged by a Holder that the Company is not
      representing to such Holder that such calculation is in compliance with Section
      13(d) of the Exchange Act and such Holder is solely responsible for any
      schedules required to be filed in accordance therewith. To the extent that
      the
      limitation contained in this Section 2.4 applies, the determination of whether
      this Warrant is exercisable (in relation to other securities owned by such
      Holder) and of which a portion of this Warrant is exercisable shall be in the
      sole discretion of a Holder, and the submission of a Notice of Exercise shall
      be
      deemed to be each Holder’s determination of whether this Warrant is exercisable
      (in relation to other securities owned by such Holder) and of which portion
      of
      this Warrant is exercisable, in each case subject to such aggregate percentage
      limitation, and the Company shall have no obligation to verify or confirm the
      accuracy of such determination. For purposes of this Section 2.4, in determining
      the number of outstanding shares of Common Stock, a Holder may rely on the
      number of outstanding shares of Common Stock as reflected in (x) the Company’s
      most recent Form 10-Q or Form 10-K, as the case may be, (y) a more recent public
      announcement by the Company or (z) any other notice by the Company or the
      Company’s Transfer Agent setting forth the number of shares of Common Stock
      outstanding. Upon the written or oral request of a Holder, the Company shall
      within two Trading Days confirm orally and in writing to such Holder the number
      of shares of Common Stock then outstanding. In any case, the number of
      outstanding shares of Common Stock shall be determined after giving effect
      to
      the conversion or exercise of securities of the Company, including this Warrant,
      by such Holder or its affiliates since the date as of which such number of
      outstanding shares of Common Stock was reported. The provisions of this Section
      2.4 may be waived by such Holder, at the election of such Holder, upon not
      less
      than 61 days’ prior notice to the Company, and the provisions of this Section
      2.4 shall continue to apply until such 61st
      day (or
      such later date, as determined by such Holder, as may be specified in such
      notice of waiver).

    

    

    
      
         

      

      
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    3.     COVENANTS
      OF
      THE COMPANY.

     

    3.1.     Covenants
      as to Exercise Shares. 
      The Company covenants and agrees that all Exercise 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.  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, 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.

     

    3.3.     Notices
      of Record Date and Certain Other Events. 
In
      the event of any taking by the Company of a record of the holders of any class
      of securities for the purpose of determining the holders thereof who are
      entitled to receive any dividend (other than a cash dividend which is the same
      as cash dividends paid in previous quarters) or other distribution, the Company
      shall mail to the Holder, at least 20 days prior to the date on which any such
      record is to be taken for the purpose of such dividend or distribution, a notice
      specifying such date.  In the event of any voluntary dissolution,
      liquidation or winding up of the Company, the Company shall mail to the Holder,
      at least 20 days prior to the date of the occurrence of any such event, a notice
      specifying such date. In the event the Company authorizes or approves, enters
      into any agreement contemplating, or solicits stockholder approval for any
      Fundamental Transaction, as defined in Section 7 herein, the Company shall
      mail
      to the Holder, at least twenty days prior to the date of the occurrence of
      such
      event, a notice specifying such date.

     

    
      
         

      

      
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    4.     [INTENTIONALLY
      OMITTED]

     

    5.     ADJUSTMENT
      OF EXERCISE PRICE AND SHARES.

     

    (a) 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 Exercise Shares subject to this Warrant.

     

    (b) 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, without payment
      therefor,  

     

    (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 5(a) 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 5(a) 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 (including cash in the cases referred to in clauses (ii) and (iii)
      above) 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.

    

    
      
         

      

      
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    (c) Upon
      the
      occurrence of each adjustment pursuant to this Section 5, the Company at its
      expense will, at the written request of the Holder, 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 Exercise Shares or other
      securities issuable upon exercise of this Warrant (as applicable), describing
      the transactions giving rise to such adjustments and showing in 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.

    

    6.     FRACTIONAL
      SHARES.  No
      fractional shares shall be issued upon the exercise of this Warrant as a
      consequence of any adjustment pursuant hereto.  All Exercise 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 shall, 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 an Exercise Share by such fraction.

     

    7.     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) 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 5 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, at the
      option of the Holder, (a) upon exercise of this Warrant, 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.  
      For
      purposes of any such exercise, the determination of the Exercise Price shall
      be
      appropriately adjusted to apply to such Alternate Consideration based on the
      amount of Alternate Consideration issuable in respect of one share of Common
      Stock in such Fundamental Transaction, and the Company shall apportion the
      Exercise Price among the Alternate Consideration in a reasonable manner
      reflecting the relative value of any different components of the Alternate
      Consideration.  If holders of Common Stock are given any choice as to the
      securities, cash or property to be received in a Fundamental Transaction, then
      the Holder shall be given the same choice as to the Alternate Consideration
      it
      receives upon any exercise of this Warrant following such Fundamental
      Transaction.  To the extent necessary to effectuate the foregoing
      provisions, any successor to the Company or surviving entity in such Fundamental
      Transaction shall issue to the Holder a new warrant consistent with the
      foregoing provisions and evidencing the Holder’s right to exercise such warrant
      into Alternate Consideration. The terms of any agreement pursuant to which
      a
      Fundamental Transaction is effected shall include terms requiring any such
      successor or surviving entity to comply with the provisions of this Section
      7
      and insuring that this Warrant (or any such replacement security) will be
      similarly adjusted upon any subsequent transaction analogous to a Fundamental
      Transaction.

     

    
      
         

      

      
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    8.     NO
      STOCKHOLDER RIGHTS.  This
      Warrant in and of itself shall not entitle the Holder to any voting rights
      or
      other rights as a stockholder of the Company.

     

    9.     TRANSFER
      OF WARRANT.  Subject
      to applicable laws, this Warrant and all rights hereunder are transferable,
      by
      the Holder in person or by duly authorized attorney, upon delivery of this
      Warrant and the form of assignment attached hereto to any transferee designated
      by Holder.

     

    10.     LOST,
      STOLEN, MUTILATED OR DESTROYED WARRANT.  If
      this
      Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms
      as to indemnity or otherwise as it may reasonably impose (which shall, in the
      case of a mutilated Warrant, include the surrender thereof), issue a new Warrant
      of like denomination and tenor as the Warrant so lost, stolen, mutilated or
      destroyed.  Any such new Warrant shall constitute an original contractual
      obligation of the Company, whether or not the allegedly lost, stolen, mutilated
      or destroyed Warrant shall be at any time enforceable by anyone.

     

    11.     NOTICES,
      ETC.  All
      notices required or permitted hereunder shall be in writing and shall be deemed
      effectively given: (a) upon personal delivery to the party to be notified,
      (b) when sent by confirmed telex or facsimile if sent during normal
      business hours of the recipient, if not, then on the next business day,
      (c) five days after having been sent by registered or certified mail,
      return receipt requested, postage prepaid, or (d) one day after deposit
      with a nationally recognized overnight courier, specifying next day delivery,
      with written verification of receipt.  All communications shall be sent to
      the Company at the address listed on the signature page hereto and to Holder
      at
      the applicable address set forth on the applicable signature page to the
      Subscription Agreement or at such other address as the Company or Holder may
      designate by 10 days advance written notice to the other parties
      hereto.

      

    12.     ACCEPTANCE. 
      Receipt
      of this Warrant by the Holder shall constitute acceptance of and agreement
      to
      all of the terms and conditions contained herein.

     

    13.     GOVERNING
      LAW.  This
      Warrant and all rights, obligations and liabilities hereunder shall be governed
      by the laws of the State of New York.

     

    [REMAINDER
      OF PAGE INTENTIONALLY LEFT BLANK]

     

    
      
         

      

      
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    IN
      WITNESS WHEREOF,
      the
      Company has caused this Warrant to be executed by its duly authorized officer
      as
      of May 4, 2007.

     

     

    ACACIA
      RESEARCH CORPORATION 

    

    

    

    By:____________________________

    Name:__________________________

    Title:___________________________

     

    

    
      
         

      

      
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    NOTICE
      OF EXERCISE

     

    TO: 
      ACACIA
      RESEARCH CORPORATION 

     

    (1)      
      o  The
      undersigned hereby elects to purchase ____________________ shares of the Acacia
      Research-CombiMatrix Common Stock (the “Common
      Stock”)
      of
ACACIA
      RESEARCH CORPORATION  (the
      “Company”)
      pursuant to the terms of the attached Warrant, and tenders herewith payment
      of
      the exercise price in full, together with all applicable transfer taxes, if
      any.

     

     o  The
      undersigned hereby elects to purchase __________________ shares of Common Stock
      of the Company pursuant to the terms of the net exercise provisions set forth
      in
      Section 2.1 of the attached Warrant, and shall tender payment of all
      applicable transfer taxes, if any.

     

    (2)      
      Please
      issue a certificate or certificates representing said shares of Common Stock
      of
      the Company in the name of the undersigned or in such other name as is specified
      below:

     

     

    (Name)

     

     

     

    (Address)

     

    

    

    

            _____________________________

    
      
        
          	(Date)	
                  (Signature)

                

        

      

    

    

    

             _____________________________

            (Print
      name)

     

     

    
      
         

      

      
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    ASSIGNMENT
      FORM

     

    (To
      assign the foregoing Warrant, execute this form and supply required
      information.  Do not use this form to purchase shares.)

     

    FOR
      VALUE RECEIVED,
      the
      foregoing Warrant and all rights evidenced thereby are hereby assigned
      to

     

    
      	Name:	
              _____________________________

            

    

    (Please
      Print)

     

    
      	Address:	
              _____________________________

            

    

    (Please
      Print)

    

     

    Dated:                         
      , 20___

     

     

      

    Holder’s
      Signature: 

     

    Holder’s
      Address:

     

     

    

     

    NOTE: 
      The signature to this Assignment Form must correspond with the name as it
      appears on the face of the Warrant, without alteration or enlargement or any
      change whatever.  Officers of corporations and those acting in a fiduciary
      or other representative capacity should file proper evidence of authority to
      assign the foregoing Warrant.

     

     

     

    -11-Form of Securities Purchase Agreement

    Exhibit
      10.1

    

    SECURITIES
      PURCHASE AGREEMENT

    

    This
      Securities Purchase Agreement (this “Agreement”)
      is
      made as of the date set forth below between Acacia Research Corporation, a
      Delaware corporation (the “Company”),
      and
      the undersigned (the “Investor”),
      as
      follows: 

     

    1.     The
      Company has authorized the sale and issuance to certain investors of up to
      7,457,627 units
      (the “Units”),
      each
      consisting of (i) one share (the “Share”
and
      collectively the “Shares”)
      of its
      Acacia Research-CombiMatrix Common Stock, par value $0.001 per share (the
“Common
      Stock”)
      and
      (ii) one warrant (the “Warrant”
      and
      collectively the “Warrants”)
      to
      purchase 1.5 Shares of Common Stock (and the fractional amount being the
“Warrant
      Ratio”)
      at an
      exercise price of Fifty-five Cents (55¢) per share, in substantially the form
      attached hereto as Exhibit
      A,
      subject
      to adjustment by the Company’s Board of Directors, or a committee thereof, for a
      purchase price of Seventy-three and 75/100 Cents (73.75¢) per Unit (the
“Purchase
      Price”).
      The
      shares issuable upon the exercise of the Warrants are referred to herein as
      the
“Warrant
      Shares”
and,
      together with the Units, the Shares and the Warrants, are referred to herein
      as
      the “Securities.”

     

    2.     The
      offering and sale of the Securities (the “Offering”)
      is
      being made pursuant to the Base Prospectus (defined below) and the exhibits
      thereto and the documents incorporated therein by reference filed by the Company
      with the Securities and Exchange Commission (the “Commission”),
      if
      applicable, certain preliminary prospectuses that have or will be filed with
      the
      Commission and delivered to the Investor on or prior to the date hereof (the
      “Time
      of Sale Prospectus”),
      and a
      Prospectus Supplement (defined below) containing certain supplemental
      information regarding the Securities and terms of the Offering that will be
      filed with the Commission and delivered, or otherwise made available, to the
      Investor along with the Company’s counterpart to this Agreement 

     

    3.     At
      the
      Closing (defined below), the Company will sell to the Investor, and the Investor
      will purchase from the Company, upon the terms and conditions set forth herein,
      the number of Units set forth on the last page of this Agreement (the
“Signature
      Page”)
      for
      the aggregate purchase price therefor set forth on the Signature
      Page.

     

    4.     The
      Company proposes to enter into substantially this same form of Securities
      Purchase Agreement with certain other investors (the “Other
      Investors”)
      and
      expects to complete sales of Units to them for an aggregate purchase price
      not
      to exceed $5,500,000. The Investor and the Other Investors are hereinafter
      sometimes collectively referred to as the “Investors,”
and
      this Agreement and the Securities Purchase Agreement executed by the Other
      Investors are hereinafter sometimes collectively referred to as the
“Agreements.”

     

    5.     In
      the
      event that the Warrant Shares are exchangeable for shares of CombiMatrix
      Corporation (the “New
      Company Shares”)
      pursuant to a spin-out transaction of CombiMatrix Corporation from the Company
      (the “Spin
      Out”),
      then
      promptly following the effective date of the Spin Out (the “Spin
      Out Date”),
      but
      in any event no later than 30 days after the Spin Out Date (the “Filing
      Deadline”),
      CombiMatrix Corporation shall file registration statement on Form S-3, if such
      form is available to CombiMatrix Corporation, covering the resale of the New
      Company Shares, in an amount sufficient to cover the resale of the New Company
      Shares issuable upon exchange of the Warrant Shares, in accordance with the
      terms of this Section 5. In the event that Form S-3 is unavailable and/or
      inappropriate for such a registration of the New Company Shares, CombiMatrix
      Corporation shall use such other form or forms as are available and appropriate
      for such a registration. 

     

    5.1     If
      a
      registration statement covering the New Company Shares is not filed with the
      SEC
      on or prior to the Filing Deadline, the Company shall cause CombiMatrix
      Corporation to make pro rata payments to each Investor, as liquidated damages
      and not as a penalty, in an amount equal to 1.0% of the fair market value of
      the
      New Company Shares issuable upon the exercise of such Investor’s Warrants or pro
      rata for any portion thereof following the Filing Deadline for which no
      registration statement is filed with respect to the New Company Shares. Such
      payments shall constitute the Investors’ exclusive monetary remedy for such
      events, but shall not affect the right of the Investors to seek injunctive
      relief. Such payments shall be made to each Investor in cash. For purposes
      of
      the above calculation, the “fair market value” of one share of New Company
      Shares shall mean (i) the average of the closing sales prices for New Company
      Shares on the Nasdaq Global Market or other trading market where such security
      is listed or traded as reported by Bloomberg Financial Markets (or a comparable
      reporting service of national reputation selected by CombiMatrix Corporation
      and
      reasonably acceptable to the Investors if Bloomberg Financial Markets is not
      then reporting sales prices of such security) (collectively, “Bloomberg”)
      for
      the 10 consecutive trading days immediately preceding such date, or (ii) if
      the
      Nasdaq Global Market is not the principal trading market for the New Company
      Shares, the average of the reported sales prices reported by Bloomberg on the
      principal trading market for the New Company Shares during the same period,
      or,
      if there is no sales price for such period, the last sales price reported by
      Bloomberg for such period, or (iii) if neither of the foregoing applies, the
      last sales price of such security in the over-the-counter market on the pink
      sheets or bulletin board for such security as reported by Bloomberg, or if
      no
      sales price is so reported for such security, the last bid price of such
      security as reported by Bloomberg or (iv) if fair market value cannot be
      calculated as of such date on any of the foregoing bases, the fair market value
      shall be as determined by the Board of Directors of CombiMatrix Corporation
      in
      the exercise of its good faith judgment.

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    5.2     CombiMatrix
      Corporation shall use its commercially reasonable efforts to cause the
      registration statement to be declared effective under the Securities Act as
      promptly as possible after the filing thereof. If (A) a registration statement
      covering the New Company Shares is not declared effective by the SEC prior
      to
      the earlier of (i) five (5) business days after the SEC shall have informed
      CombiMatrix Corporation that no review of the registration statement will be
      made or that the SEC has no further comments on the registration statement
      or
      (ii) the 120th day after the Spin Out Date, or (B) after the registration
      statement has been declared effective by the SEC, sales cannot be made pursuant
      to such registration statement for any reason (including without limitation
      by
      reason of a stop order, or CombiMatrix Corporation’s failure to update the
      registration statement), but excluding the inability of any Investor to sell
      its
      New Company Shares due to market conditions and except as excused pursuant
      to
      clause (c) below, then CombiMatrix Corporation shall make pro rata payments
      to
      each Investor, as liquidated damages and not as a penalty, in an amount equal
      to
      1.0% of the fair market value of the New Company Shares issuable upon the
      exercise of such Investor’s Warrants or pro rata for any portion thereof
      following the date by which such registration statement should have been
      effective (the “Blackout
      Period”).
      Such
      payments shall constitute the Investors’ exclusive monetary remedy for such
      events, but shall not affect the right of the Investors to seek injunctive
      relief. The amounts payable as liquidated damages pursuant to this paragraph
      shall be paid monthly within three (3) business days of the last day of each
      month following the commencement of the Blackout Period until the termination
      of
      the Blackout Period. Such payments shall be made to each Investor in
      cash.

     

    5.3     For
      not
      more than twenty (20) consecutive days or for a total of not more than
      forty-five (45) days in any twelve (12) month period, CombiMatrix Corporation
      may delay the disclosure of material non-public information concerning the
      CombiMatrix Corporation, by suspending the use of any prospectus included in
      any
      registration contemplated by this Section 5.3 containing such information,
      the
      disclosure of which at the time is not, in the good faith opinion of CombiMatrix
      Corporation, in the best interests of CombiMatrix Corporation (an “Allowed
      Delay”);
      provided, that CombiMatrix Corporation shall promptly (i) notify the Investors
      in writing of the existence of (but in no event, without the prior written
      consent of an Investor, shall CombiMatrix Corporation disclose to such Investor
      any of the facts or circumstances regarding) material non-public information
      giving rise to an Allowed Delay, (ii) advise the Investors in writing to cease
      all sales under the registration statement until the end of the Allowed Delay
      and (c) use commercially reasonable efforts to terminate an Allowed Delay as
      promptly as practicable.

     

    5.4     CombiMatrix
      Corporation shall use its best efforts to keep such registration statement
      effective (pursuant to Rule 415 if available) at all times until such date
      as is
      the earlier of (i) the date on which all such New Company Shares have been
      sold
      and (ii) the date on which such New Company Shares may be immediately sold
      without restriction (including without limitation as to volume restrictions
      by
      each holder thereof) without registration under the Securities Act pursuant
      to
      Rule 144(k).

     

    6.     The
      Company shall have the sole right to accept offers to purchase the Units and
      may
      reject any such offer, in its sole and absolute discretion, in whole or in
      part.
      No offer by the Investor to buy Units will be accepted and no part of the
      purchase price will be delivered to the Company until the Company has accepted
      such offer by countersigning a copy of this Agreement, and any such offer may
      be
      withdrawn or revoked, without obligation or commitment of any kind, at any
      time
      prior to the Company sending (orally, in writing or by electronic mail) notice
      of its acceptance of such offer. An indication of interest in response to the
      Investor signing this Agreement will involve no obligation or commitment of
      any
      kind until this Agreement is accepted and countersigned by the Company and
      notice of such acceptance has been sent as aforesaid.

     

    7.     The
      Company represents and warrants to the Investor as of the date hereof and as
      of
      the Closing Date, as follows:

     

    (a) Registration
      Statement.
      The
      Company has prepared and filed in conformity with the requirements of the
      Securities Act of 1933, as amended (the “Securities
      Act”),
      and
      published rules and regulations thereunder (the “Rules
      and Regulations”)
      adopted by the Commission a “shelf” Registration Statement (as hereinafter
      defined) on Form S-3 (No. 333-133529), which was declared by the Commission
      to
      be effective under the Securities Act as of May 26, 2006 (the “Effective
      Date”),
      including a Base Prospectus, dated as of the Effective Date, relating to the
      Securities (the “Base
      Prospectus”),
      and
      such amendments and supplements thereto as may have been required to the date
      of
      this Agreement. The Company will next file with the Commission pursuant to
      Rule
      424(b) under the Securities Act a final prospectus supplement to the Base
      Prospectus (a “Prospectus
      Supplement”)
      describing the Units and the offering thereof, in such form as has been provided
      to the Investor.

     

    
      
         

      

      
        -2-

        
          

        

      

      
         

      

    

    The
      term
“Registration
      Statement”
      as used
      in this Agreement means the registration statement (including all exhibits,
      financial schedules and all documents and information deemed to be a part of
      the
      Registration Statement pursuant to Rule 430A or 434(d) under the Securities
      Act), as of the Effective Date and as amended and/or supplemented to the date
      of
      this Agreement. The Registration Statement has been declared effective under
      the
      Securities Act and no stop order preventing or suspending the effectiveness
      of
      the Registration Statement or suspending or preventing the use of the Prospectus
      (as defined below) has been issued by the Commission and no proceedings for
      that
      purpose have been instituted or, to the Company’s knowledge, are contemplated by
      the Commission.

     

    The
      term
“Prospectus”
      as used
      in this Agreement means the Base Prospectus together with the Prospectus
      Supplement, except that if such Base Prospectus is amended or supplemented
      prior
      to the date on which the Prospectus Supplement was first filed pursuant to
      Rule
      424, the term “Prospectus”
      shall
      refer to the Base Prospectus as so amended or supplemented and as supplemented
      by the Prospectus Supplement. Any reference herein to the Registration
      Statement, the Base Prospectus, any Prospectus Supplement or the Prospectus
      shall be deemed to refer to and include the documents incorporated by reference
      therein pursuant to Item 12 of Form S-3 (the “Incorporated
      Documents”),
      which
      were filed under the Securities Exchange Act of 1934, as amended (the
“Exchange
      Act”)
      and
      any reference herein to the terms “amend,” “amendment,” or “supplement” with
      respect to the Registration Statement, the Prospectus Supplement or the
      Prospectus shall be deemed to refer to and include (i) the filing of any
      document under the Exchange Act after the Effective Date, or the date of the
      Prospectus, as the case may be, which is incorporated by reference and (ii)
      any
      such document so filed. If the Company has filed an abbreviated registration
      statement to register additional Securities pursuant to Rule 462(b) under the
      Rules (the “462(b)
      Registration Statement”),
      then any
      reference herein to the Registration Statement shall also be deemed to include
      such 462(b) Registration Statement.

     

    (b) Registration
      Statement and Prospectus.
      On the
      Effective Date, upon the filing or first delivery to the Investors of the
      Prospectus, as of the date hereof, and at the Closing Date, the Registration
      Statement (and any post-effective amendment thereto) and the Prospectus (as
      amended or as supplemented if the Company shall have filed with the Commission
      any amendment or supplement to the Registration Statement or the Prospectus)
      complied and will comply, in all material respects, with the requirements of
      the
      Securities Act and the Rules and Regulations and the Exchange Act and the rules
      and regulations of the Commission thereunder and did not at the Effective Date,
      does not as of the date hereof and will not as of the Closing Date, contain
      any
      untrue statement of a material fact or omit to state any material fact required
      to be stated therein or necessary in order to make the statements therein (in
      light of the circumstances under which they were made, in the case of the
      Prospectus) not misleading. Notwithstanding the foregoing, none of the
      representations and warranties in this paragraph 7(b) shall apply to statements
      in, or omissions from, the Registration Statement or the Prospectus, or any
      amendment or supplement thereto made in reliance upon, and in conformity with,
      information herein or otherwise furnished in writing by or on behalf of any
      Investor to the Company expressly for use in the Registration Statement or
      the
      Prospectus or any amendment or supplement thereto. The Incorporated Documents,
      at the time they became effective or were filed with the Commission, complied
      in
      all material respects with the requirements of the Exchange Act and did not
      contain any untrue statement of a material fact or omit to state any material
      fact required to be stated therein or necessary in order to make the statements
      therein, in light of the circumstances under which they were made, not
      misleading. The Company has not distributed and will not distribute, prior
      to
      the completion of the distribution of the Securities, any offering material
      in
      connection with the offering and sale of the Securities, other than the
      Registration Statement and the Prospectus.

     

    (c) Subsidiaries.
      The
      Company has no significant subsidiaries (as such term is defined in Rule 1-02
      of
      Regulation S-X promulgated by the Commission) other than as listed in
Schedule
      I
      attached
      hereto (collectively, the “Subsidiaries”).
      All
      of the issued and outstanding shares of capital stock of each of the
      Subsidiaries have been duly and validly authorized and issued and are fully
      paid, nonassessable and free of preemptive and similar rights to subscribe
      for
      or purchase securities, and, except as listed on Schedule
      I
      attached
      hereto or otherwise described in the Registration Statement and Prospectus,
      the
      Company owns directly or indirectly, free and clear of any security interests,
      claims, liens, proxies, equities or other encumbrances, all of the issued and
      outstanding shares of such stock.

     

    
      
         

      

      
        -3-

        
          

        

      

      
         

      

    

    (d) Financial
      Statements.
      The
      consolidated financial statements of the Company, together with the related
      schedules and notes thereto, set forth or incorporated by reference in the
      Registration Statement and the Prospectus comply in all material respects with
      the applicable requirements of the Securities Act and the Exchange Act, as
      applicable, and fairly present, in all material respects, (i) the consolidated
      financial condition of the Company and its Subsidiaries as of the dates
      indicated and (ii) the consolidated results of operations, stockholders’ equity
      and changes in cash flows of the Company and the Subsidiaries for the periods
      therein specified; and such financial statements and related schedules and
      notes
      thereto, comply, in all material respects, as to form with the applicable
      accounting requirements under the Securities Act and have been prepared in
      conformity with United States generally accepted accounting principles,
      consistently applied throughout the periods involved (except as otherwise stated
      therein and subject, in the case of unaudited financial statements, to the
      absence of footnotes and normal year-end adjustments). No other financial
      statements or schedules are required by the Securities Act and the Rules and
      Regulations to be included in the Registration Statement or
      Prospectus.

     

    (e) Independent
      Accountants.
      PricewaterhouseCoopers, LLP (the “Auditors”),
      whose
      report with respect to the audited consolidated financial statements and
      schedules of the Company and its Subsidiaries included in the Prospectus, or
      the
      Registration Statement, or incorporated by reference therein is, and during
      the
      periods covered by its reports, was an independent public accounting firm within
      the meaning of the Securities Act and the Rules and Regulations.

     

    (f) Organization.
      Each of
      the Company and its Subsidiaries has been duly incorporated or otherwise
      organized and is validly existing as a corporation in good standing under the
      laws of its jurisdiction of incorporation or organization (as applicable).
      Each
      of the Company and its Subsidiaries has full corporate power and authority
      to
      own, lease and operate its properties and assets and to conduct its business
      as
      described in the Registration Statement and Prospectus, and is duly qualified
      to
      do business as a foreign corporation and is 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, except where the failure to
      be
      so qualified or be in good standing, as the case may be, would not, individually
      or in the aggregate, have or reasonably be expected 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 (a “Material
      Adverse Effect”).

     

    (g) No
      Material Adverse Effect.
      Except
      as set forth in the Registration Statement or the Prospectus, subsequent to
      the
      respective dates as of which information is given in the Registration Statement
      and the Prospectus, there has not been (i) any material adverse change in the
      business, properties, management, financial condition or results of operations
      of the Company and its subsidiaries taken as a whole, including any material
      loss or interference with its respective business from fire, explosion, flood
      or
      other calamity, whether or not covered by insurance, or from any labor dispute
      or court or governmental action, order or decree, (ii) any transaction that
      is
      material to the Company and its Subsidiaries taken as a whole, (iii) any
      obligation, direct or contingent (including any off balance sheet obligations),
      incurred by the Company or its Subsidiaries, which is material to the Company
      and its Subsidiaries taken as a whole, (iv) any change in the capital stock
      or
      outstanding indebtedness of the Company or its Subsidiaries (subject to the
      issuance of shares of Common Stock upon exercise of stock options or warrants
      disclosed as outstanding in the Registration Statement and Prospectus and the
      grant of options under existing stock option plans described in the Registration
      Statement and Prospectus) or (v) any dividend or distribution of any kind
      declared, paid or made on the capital stock of the Company.

     

    (h) Legal
      Proceedings.
      Except
      as set forth in the Registration Statement and the Prospectus, there is not
      pending or, to the knowledge of the Company, threatened or contemplated, any
      action, suit or proceeding to which the Company or any of its Subsidiaries
      is a
      party or of which any property or assets of the Company or any of its
      Subsidiaries is the subject before or by any court or governmental agency,
      authority or body, or any arbitrator, which, individually or in the aggregate,
      would reasonably be expected to result in any Material Adverse Effect or
      materially and adversely affect the ability of the Company to perform its
      obligations under this Agreement and the Securities Purchase
      Agreements.

     

    (i) Sufficiency
      of Disclosure.
      There
      are (i) no current or pending legal, governmental or regulatory actions, suits
      or proceedings that are required under the Securities Act to be described in
      the
      Registration Statement and Prospectus that have not been so described and (ii)
      there are no affiliate transactions, off-balance sheet transactions, contracts,
      licenses, agreements, leases or other documents of a character required to
      be
      described in the Registration Statement or the Prospectus or to be filed as
      exhibits to the Registration Statement that are not so described or filed as
      required.

     

    (j) Due
      Authorization and Enforceability.
      The
      Company has full legal power and authority to enter into this Agreement and
      the
      Securities Purchase Agreements and to consummate the transactions contemplated
      hereby and thereby. This Agreement and each of the Securities Purchase
      Agreements have been duly authorized, executed and delivered by the Company,
      and
      constitute valid, legal and binding obligations of the Company, enforceable
      in
      accordance with their terms, except as rights to indemnity hereunder may be
      limited by applicable laws and except as such enforceability may be limited
      by
      bankruptcy, insolvency, reorganization, moratorium or similar laws affecting
      the
      rights and remedies of creditors generally or subject to general principles
      of
      equity.

     

    
      
         

      

      
        -4-

        
          

        

      

      
         

      

    

    (k) The
      Shares.
      The
      Shares have been duly and validly authorized by the Company and, when issued,
      delivered and paid for in accordance with the terms of this Agreement, will
      have
      been duly and validly issued and will be fully paid and nonassessable; and
      the
      capital stock of the Company, including the AR-CombiMatrix Common Stock,
      conforms to the description thereof in the Registration Statement and
      Prospectus. Except as otherwise stated in the Registration Statement and
      Prospectus, there are no preemptive rights or other rights to subscribe for
      or
      to purchase, or any restriction upon the voting or transfer of, any shares
      of AR
      -CombiMatrix Common Stock pursuant to the Company’s charter, bylaws or any
      agreement or other instrument to which the Company is a party or by which the
      Company is bound that have not been waived or complied with.

     

    (l) The
      Warrants.
      The
      Company has the full right, power and authority to enter into the Warrants
      and
      to perform and discharge its obligations thereunder. The Warrants have been
      duly
      and validly authorized by the Company and upon delivery to the Investors at
      the
      Closing Date will be duly issued and will constitute legal, valid and binding
      obligations of the Company, enforceable in accordance with their terms, except
      as such enforceability may be limited by bankruptcy, insolvency, reorganization,
      moratorium or similar laws affecting the rights and remedies of creditors
      generally or subject to general principles of equity. The Warrant Shares have
      been duly authorized and reserved for issuance upon the exercise of the Warrants
      and when issued upon payment of the exercise price therefor will be validly
      issued, fully paid and nonassessable.

     

    (m) No
      Conflicts.
      The
      execution, delivery and performance by the Company of this Agreement, the
      Warrants, and each of the Securities Purchase Agreements and the consummation
      of
      the transactions herein and therein contemplated, including the issuance and
      sale of the Securities, will not (i) conflict with or result in a breach or
      violation of any of the terms or provisions of, or constitute a default (or
      an
      event which with notice or lapse of time or both would constitute a default)
      under, or require any consent or waiver under, or result in the execution of
      any
      lien, charge or encumbrance upon any properties or assets of the Company or
      its
      Subsidiaries pursuant to the terms of, any indenture, mortgage, deed of trust,
      loan agreement or other agreement or instrument to which the Company or any
      of
      its Subsidiaries is a party or by which the Company or any of its Subsidiaries
      is bound or to which any of the property or assets of the Company or any of
      its
      Subsidiaries is subject, (ii) result in any violation of the provisions of
      the
      charter or by-laws of the Company or any of its Subsidiaries or (iii) result
      in
      any violation of any franchise, license, permit, statute, law, rule or
      regulation applicable to the Company or any judgment, order or decree of any
      court or governmental agency or body having jurisdiction over the Company or
      any
      of its Subsidiaries or any of their properties or assets, except, in the case
      of
      each of clauses (i) and (iii) above, for any such conflict, breach, violation,
      default, lien, charge or encumbrance that would not, individually or in the
      aggregate, reasonably be expected to result in a Material Adverse
      Effect.

     

    (n) No
      Consents Required.
      No
      consent, approval, authorization, filing with or order of or registration with,
      any court or governmental agency or body, or approval of the shareholders of
      the
      Company, is required for the execution, delivery and performance of this
      Agreement, the Warrants, and each of the Securities Purchase Agreements or
      for
      the consummation of the transactions contemplated hereby and thereby, including
      the issuance or sale of the Securities by the Company, except such as have
      been
      obtained or made, and such as may be required under the securities, or blue
      sky,
      laws of any jurisdiction in connection with the offer and sale of the Units
      by
      the Company in the manner contemplated herein and in the Registration Statement
      and the Prospectus.

     

    (o) Capitalization.
      All of
      the issued and outstanding shares of capital stock of the Company, including
      the
      outstanding shares of AR-CombiMatrix Common Stock, are duly authorized and
      validly issued, fully paid and nonassessable, have been issued in compliance
      with all federal and state securities laws, were not issued in violation of
      or
      subject to any preemptive rights or other rights to subscribe for or purchase
      securities that have not been waived in writing. As of the date hereof and
      as of
      the Closing Date, the Company has or will have, as the case may be, an
      authorized, issued and outstanding capitalization as is set forth in the
      Registration Statement and the Prospectus (subject, in each case, to the
      issuance of shares of Common Stock upon exercise of stock options and warrants
      disclosed as outstanding in the Registration Statement and the Prospectus and
      grant of options under existing stock option plans described in the Registration
      Statement and the Prospectus, and such authorized capital stock conforms to
      the
      description thereof set forth in the Registration Statement and the Prospectus.
      Except as described in the Registration Statement and the Prospectus, as of
      the
      date referred to therein, the Company did not have outstanding any options,
      warrants, agreements, contracts or other rights in existence to purchase or
      acquire from the Company or any Subsidiary of the Company any shares of the
      capital stock of the Company or any Subsidiary of the Company.

     

    
      
         

      

      
        -5-

        
          

        

      

      
         

      

    

    (p) Title
      to Real and Personal Property.
      The
      Company and each of its Subsidiaries has good and valid title to all property
      (whether real or personal) described in the Registration Statement and
      Prospectus as being owned by each of them, in each case free and clear of all
      liens, claims, security interests, other encumbrances or defects except such
      as
      are described in the Registration Statement and the Prospectus and those that
      do
      not materially and adversely affect the value of such property and do not
      materially interfere with the use made of such property by the Company. All
      of
      the property described in the Registration Statement and the Prospectus as
      being
      held under lease by the Company or a Subsidiary are held thereby under valid,
      subsisting and enforceable leases.

     

    (q) Title
      to Intellectual Property.
      The
      Company and its Subsidiaries own, possess, license or have other rights to
      use
      all foreign and domestic patents, patent applications, trade and service marks,
      trade and service mark registrations, trade names, copyrights, licenses,
      inventions, trade secrets, technology, Internet domain names, know-how and
      other
      intellectual property, necessary for the conduct of CombiMatrix Group’s (as
      defined in the Prospectus) businesses as now conducted or as proposed in the
      Prospectus to be conducted (collectively, the “Intellectual
      Property”).
      Except as set forth in the Prospectus, (a) the Company has not received written
      notice, and has no knowledge of, any rights of third parties to any such
      Intellectual Property; (b) to the Company’s knowledge, there is no infringement
      by third parties of any such Intellectual Property; (c) there is no pending
      or,
      to the Company’s knowledge,
      threatened action, suit, proceeding or claim by others challenging the Company’s
      and its Subsidiaries’ rights in or to any such Intellectual Property; (d) there
      is no pending or, to the Company’s knowledge, threatened action, suit,
      proceeding or claim by others challenging the validity or scope of any such
      Intellectual Property; (e) there is no pending or, to the Company’s knowledge,
      threatened action, suit, proceeding or claim by others that CombiMatrix Group
      infringes or otherwise violates any patent, trademark, copyright, trade secret
      or other proprietary rights of others; (f) to the Company’s knowledge, there is
      no third-party U.S. patent or published U.S. patent application which contains
      claims for which an Interference Proceeding (as defined in 35 U.S.C. § 135) has
      been commenced against any patent or patent application which constitutes the
      Intellectual Property described in the Prospectus; and (g) the CombiMatrix
      Group
      has taken all steps necessary to perfect its ownership of the Intellectual
      Property, in each of clauses (a)-(g) except for such infringement, conflict
      or
      action which would not, singularly or in the aggregate, reasonably be expected
      to result in a Material Adverse Effect.

     

    (r) No
      Violation or Default.
      Neither
      the Company nor any of its Subsidiaries is (i) in violation of any provision
      of
      its charter or bylaws or similar organizational documents, (ii) is in default
      in
      any respect, and no event has occurred which, with notice or lapse of time
      or
      both, would constitute such a default, in the due performance or observance
      of
      any term, covenant, or condition of any indenture, contract, lease, mortgage,
      deed of trust, note agreement, loan agreement or other agreement, obligation,
      condition, covenant or instrument to which it is a party or by which it is
      bound
      or to which any of its property or assets is subject, or (iii) is in violation
      in any respect of any statute, law, rule, regulation, ordinance, judgment,
      order
      or decree of any court, regulatory body, administrative agency, governmental
      body, arbitrator or other authority having jurisdiction over the Company, its
      Subsidiaries or any of its properties of which it has knowledge, as applicable,
      except, with respect to clauses (ii) and (iii), any violations or defaults
      which, singularly or in the aggregate, would not reasonably be expected to
      result in a Material Adverse Effect.

     

    (s) Permits.
      The
      Company and each of its Subsidiaries has made all filings, applications and
      submissions required by, and possesses all approvals, licenses, certificates,
      certifications, clearances, consents, exemptions, marks, notifications, orders,
      permits and other authorizations issued by, the appropriate federal, state
      or
      foreign regulatory authorities necessary to conduct its businesses as described
      in the Registration Statement and the Prospectus (collectively, “Permits”),
      except for such Permits the failure of which to obtain would not reasonably
      be
      expected to result in a Material Adverse Effect, and is in compliance with
      the
      terms and conditions of all such Permits; all of such Permits held by the
      Company and each of its Subsidiaries are valid and in full force and effect;
      there is no pending or, to its knowledge, threatened action, suit, claim or
      proceeding which may cause any such Permit to be limited, revoked, cancelled,
      suspended, modified or not renewed, except for such limitations, revocations,
      cancellations, suspensions, modifications or non-renewals that would not
      reasonably be expected to result in a Material Adverse Effect; and the Company
      and each of its Subsidiaries has not received any notice of proceedings relating
      to the limitation, revocation, cancellation, suspension, modification or
      non-renewal of any such Permit which, singly or in the aggregate, if the subject
      of an unfavorable decision, ruling or finding, would reasonably be expected
      to
      result in a Material Adverse Effect, whether or not arising from transactions
      in
      the ordinary course of business and has no reason to believe that any such
      license, certificate, permit or authorization will not be renewed in the
      ordinary course.

     

    
      
         

      

      
        -6-

        
          

        

      

      
         

      

    

    (t) Taxes.
      The
      Company and its Subsidiaries have timely filed all federal, state, local and
      foreign income and franchise tax returns (or timely filed applicable extensions
      therefore) required to be filed and are not in default in the payment of any
      taxes which were payable pursuant to said returns or any assessments with
      respect thereto, other than any which the Company or any of its Subsidiaries
      is
      contesting in good faith and for which adequate reserves have been
      provided.

     

    (u) Listing.
      The
      AR-CombiMatrix Common Stock (including the Shares and the Warrant Shares) is
      registered pursuant to Section 12(g) of the Exchange Act and except for receipt
      of the Nasdaq Staff Deficiency Letter dated April 23, 2007 (regarding the
      failure to maintain the minimum trading price), the Company, in the two years
      preceding the date hereof, has not received any notification (written or oral)
      from the Nasdaq Global Market, any stock exchange, market or trading facility
      on
      which the AR-CombiMatrix Common Stock is or has been listed (or on which it
      has
      been quoted) to the effect that the Company is not in compliance with the
      listing or maintenance requirements of such exchange, market or trading
      facility. The Company shall comply with all requirements of the Nasdaq Global
      Market with respect to the issuance of the Securities and shall use its best
      efforts to have the Shares and the Warrant Shares listed on the Nasdaq Global
      Market on or before the Closing Date.

     

    (v) Internal
      Controls.
      The
      Company and each of its Subsidiaries maintains a system of internal accounting
      controls sufficient to provide reasonable assurances that (i)
      transactions
      are executed in accordance with management’s general or specific authorization;
(ii)
      transactions
      are recorded as necessary to permit preparation of financial statements in
      conformity with generally accepted accounting principles and to maintain
      accountability for assets; (iii) access to assets is permitted only in
      accordance with management’s general or specific authorization; and (iv) the
      recorded accountability for assets is compared with existing assets at
      reasonable intervals and appropriate action is taken with respect to any
      differences.

     

    (w) Disclosure
      Controls.
      The
      Company has established and maintains disclosure controls and procedures (as
      such term is defined in Rule 13a-15e and 15d-15e under the Exchange Act), which
      (i) are designed to ensure that material information relating to the Company
      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; (ii) provide for the periodic evaluation of the effectiveness of
      such
      disclosure controls and procedures as of the end of each of the Company’s
      quarterly and annual fiscal periods; and (iii), as of the end of the periods
      covered by each periodic report filed under the Exchange Act and incorporated
      by
      reference into the Prospectus, were effective in all material respects to
      perform the functions for which they were established. The Company’s auditors
      and the Audit Committee of the Board of Directors have been advised of (i)
      any
      significant deficiency in the design or operation of internal controls which
      could adversely affect the Company’s ability to record, process, summarize and
      report financial data or any material weaknesses in internal controls; or (ii)
      any fraud, whether or not material, that involves management or other employees
      who have a significant role in the Company’s internal controls. Since the date
      of the most recent evaluation of such disclosure controls and procedures, there
      have been no changes that have materially affected, or are reasonably likely
      to
      materially affect, the Company’s internal control over financial reporting,
      including any corrective actions with regard to significant deficiencies and
      material weaknesses.

     

    (x) No
      Undisclosed Relationships.
      No
      relationship, direct or indirect, exists between or among the Company on the
      one
      hand and the directors, officers, stockholders, customers or suppliers of the
      Company on the other hand which is required to be described in the Prospectus
      and which is not so described.

     

    (y) No
      Registration Rights.
      Except
      as described in the Prospectus, no person or entity has the right, contractual
      or otherwise, to require registration of shares of AR-CombiMatrix Common Stock
      or other securities of the Company because of the filing or effectiveness of
      the
      Registration Statement or otherwise, except for persons and entities who have
      expressly waived such right or who have been given proper notice and have failed
      to exercise such right within the time or times required under the terms and
      conditions of such right, and the Company is not required to file any
      registration statement for the registration of any securities of any person
      or
      register any such securities pursuant to any other registration statement filed
      by the Company under the Securities Act for a period of at least 180 days after
      the Effective Date.

     

    (z) Sarbanes-Oxley
      Act.
      The
      principal executive officer and principal financial officer of the Company
      have
      made all certifications required by Sections 302 and 906 of the Sarbanes-Oxley
      Act of 2002 and the rules and regulations promulgated in connection therewith
      (the “Sarbanes:Oxley
      Act”)
      with
      respect to all reports, schedules, forms, statements and other documents
      required to be filed by it with the Commission, and the statements contained
      in
      any such certification are complete and correct.
      The
      Company, and to its knowledge after due inquiry, all of the Company’s directors
      or officers, in their capacities as such, is in compliance in all material
      respects with all applicable effective provisions of the Sarbanes-Oxley Act
      (and
      intends to comply with all applicable provisions that are not yet effective
      upon
      effectiveness).

     

    
      
         

      

      
        -7-

        
          

        

      

      
         

      

    

    (aa) Compliance
      with Environmental Laws.
      (i) The
      Company and each of its Subsidiaries is in compliance in all material respects
      with all rules, laws and regulation relating to the use, treatment, storage
      and
      disposal of toxic substances and protection of human health and safety or the
      environment (“Environmental
      Laws”)
      which
      are applicable to its business, except where the failure to comply would not
      reasonably be expected to result in a Material Adverse Effect; (ii) neither
      the
      Company nor its Subsidiaries has received any written notice from any
      governmental authority or third party of an asserted claim under Environmental
      Laws; (iii) the Company and each of its Subsidiaries has received all material
      permits, licenses or other approvals required of it under applicable
      Environmental Laws to conduct its business and is in compliance with all
      material terms and conditions of any such permit, license or approval, except
      where the failure to receive or comply would not reasonably be expected to
      result in a Material Adverse Effect; (iv) to the Company’s knowledge after
      reasonable due inquiry, no facts currently exist that will require the Company
      or any of its Subsidiaries to make future material capital expenditures to
      comply with Environmental Laws; and (v) no property which is or has been owned,
      leased or occupied by the Company or its Subsidiaries has been designated as
      a
      Superfund site pursuant to the Comprehensive Environmental Response,
      Compensation of Liability Act of 1980, as amended (42 U.S.C. Section 9601,
      et.
      seq,) (“CERCLA”)
      or
      otherwise designated as a contaminated site under applicable state or local
      law.
      Neither the Company nor any of its Subsidiaries has been named as a “potentially
      responsible party” under CERCLA.

     

    (bb) Compliance
      with ERISA.
      Each of
      the Company and its Subsidiaries has fulfilled its obligations, if any, under
      the minimum funding standards of Section 302 of the United States Employee
      Retirement Income Security Act of 1974 (“ERISA”)
      and
      the regulations and published interpretations thereunder with respect to each
      “plan”
(as
      defined in Section 3(3) of ERISA and such regulations and published
      interpretations) in which employees of the Company and its Subsidiaries are
      eligible to participate and each such plan is in compliance in all material
      respects with the presently applicable provisions of ERISA and such regulations
      and published interpretations. No “prohibited
      transaction”
(as
      defined in Section 406 of ERISA, or Section 4975 of the Internal Revenue Code
      of
      1986, as amended from time to time (the “Code”))
      has
      occurred with respect to any employee benefit plan which could reasonably be
      expected to result in a Material Adverse Effect. The Company and each of its
      Subsidiaries has not incurred any unpaid liability to the Pension Benefit
      Guaranty Corporation (other than for the payment of premiums in the ordinary
      course) or to any such plan under Title IV of ERISA,

     

    (cc) No
      Labor Disputes.
      No
      labor problem or dispute with the employees of the Company or any of its
      Subsidiaries exists or, to the Company’s knowledge, is threatened or imminent,
      which would reasonably be expected to result in a Material Adverse Effect.
      The
      Company is not aware that any key employee or significant group of employees
      of
      the Company or any of its Subsidiaries plans to terminate employment with the
      Company or any such Subsidiary.

     

    (dd) Insurance.
      The
      Company and each of its Subsidiaries is insured by insurers of recognized
      financial responsibility against such losses and risks and in such amounts
      as
      are prudent and customary in the businesses in which they are engaged or propose
      to engage after giving effect to the transactions described in the Prospectus;
      all policies of insurance and fidelity or surety bonds insuring the Company
      and
      each of its Subsidiaries and their businesses, assets, employees, officers
      and
      directors are in full force and effect; the Company and each of its Subsidiaries
      is in compliance with the terms of such policies and instruments in all material
      respects; and the Company and each of its Subsidiaries has no reason to believe
      that it will not be able to renew its existing insurance coverage as and when
      such coverage expires or to obtain similar coverage from similar insurers as
      may
      be necessary to continue its business at a cost that is not materially greater
      than the current cost, except where the failure to obtain would not reasonably
      be expected to result in a Material Adverse Effect.

     

    (ee) No
      Stabilization.
      Neither
      the Company nor any of its Subsidiaries nor, to its knowledge after reasonable
      due inquiry, any of their officers, directors, affiliates or controlling persons
      has taken or will take, directly or indirectly, any action designed or intended
      to stabilize or manipulate the price of any security of the
      Company.

     

    (ff) Investment
      Company Act.
      Neither
      the Company nor any of its Subsidiaries is or, after giving effect to the
      offering and sale of the Securities and the application of the proceeds thereof
      as described in the Prospectus, will be required to register as an “investment
      company” as defined in the Investment Company Act of 1940, as
      amended.

     

    
      
         

      

      
        -8-

        
          

        

      

      
         

      

    

    (gg) No
      Broker’s Fees.
      Neither
      the Company nor any of its Subsidiaries is a party to any contract, agreement
      or
      understanding with any person (other than this Agreement) that would give rise
      to a valid claim against the Company or its Subsidiaries for a brokerage
      commission, finder’s fee or like payment in connection with the offering and
      sale of the Securities.

     

    (hh) Contracts.
      Each
      description of a contract, document or other agreement in the Registration
      Statement and the Prospectus accurately reflects in all material respects the
      terms of the underlying contract, document or other agreement. Each contract,
      document or other agreement described in the Registration Statement and
      Prospectus or listed in the exhibits to the Registration Statement or
      incorporated therein by reference is in full force and effect, unless validly
      terminated in accordance with the provisions thereof, and is valid and
      enforceable by and against the Company or its Subsidiary, as the case may be,
      in
      accordance with its terms, except as such enforceability may be limited by
      bankruptcy, insolvency, reorganization, moratorium or similar laws affecting
      the
      rights and remedies of creditors generally and subject to general principles
      of
      equity, Neither the Company nor any of its Subsidiaries, if a Subsidiary is
      a
      party, nor to the Company’s knowledge, any other party, is in default in the
      observance or performance of any term or obligation to be performed by it under
      any such agreement, and no event has occurred which with notice or lapse of
      time
      or both would constitute such a default, in any such case which default or
      event, individually or in the aggregate, would reasonably be expected to result
      in a Material Adverse Effect.

     

    (ii) Forward-Looking
      Statements.
      No
      forward-looking statement (within the meaning of Section 27A of the Securities
      Act and Section 21E of the Exchange Act) contained in the Registration Statement
      and the Prospectus has been made or reaffirmed without a reasonable basis or
      has
      been disclosed other than in good faith.

     

    (jj) Foreign
      Corrupt Practices.
      Neither
      the Company nor any of its Subsidiaries, nor, to the knowledge of the Company
      after reasonable due inquiry, any director, officer, agent or employee of the
      Company or its Subsidiaries, has, directly or indirectly, while acting on behalf
      of the Company or its Subsidiaries (i) used any corporate funds for unlawful
      contributions, gifts, entertainment or other unlawful expenses relating to
      political activity; (ii) made any unlawful payment to foreign or domestic
      government officials or employees or to foreign or domestic political parties
      or
      campaigns from corporate funds; (iii) violated any provision of the Foreign
      Corrupt Practices Act of 1977, as amended; (iv) made any other unlawful bribe,
      rebate, payoff, influence, kickback or payment to any foreign or domestic
      government official or employee.

     

    (kk) Off-Balance
      Sheet Arrangements.
      There
      are no material off balance sheet arrangements (as defined in Item 303 of
      Regulation S-K) that have or would reasonably be likely to have a material
      current or future effect on the Company’s financial condition, revenues or
      expenses, changes in financial condition, results of operations, liquidity,
      capital expenditures or capital resources, including those off-balance sheet
      transactions described in the Commission’s Statement about Management’s
      Discussion and Analysis of Financial Conditions and Results of Operations
      (Release Nos 33-8056; 34-45321; FR-61), required to be described in the
      Prospectus which have not been so described.

     

    (ll) Regulatory
      Filings.
      Each of
      the Company and its Subsidiaries has filed with the applicable regulatory
      authorities all filings, declarations, listings, registrations, reports and
      submissions required to be filed; all
      such
      filings, declarations, listings, registrations, reports or submissions were
      in
      compliance with applicable laws when filed and no deficiencies have been
      asserted by any applicable regulatory authority with respect to any such
      filings, declarations, listings, registrations, repots or submissions To the
      Company’s knowledge after reasonable due inquiry, there are no affiliations or
      associations between any member of the National Association of Securities
      Dealers, Inc. (the “NASD”)
      and
      any of the Company’s officers, directors or any five percent (5%) or greater
      shareholders of the Company, except as set forth in the Registration Statement
      and the Prospectus or otherwise disclosed in writing to the
      Investor.

     

    8.     Representations,
      Warranties and Covenants of the Investor.

     

    8.1     The
      Investor represents and warrants to, and covenants with, the Company that
      (a) the Investor is knowledgeable, sophisticated and experienced in making,
      and is qualified to make decisions with respect to, investments in shares
      presenting an investment decision like that involved in the purchase of the
      Units, including investments in securities issued by the Company and investments
      in comparable companies, and has requested, received, reviewed and considered
      all information it deemed relevant in making an informed decision to purchase
      the Units, (b) the Investor has answered all questions on the Signature
      Page and the Investor Questionnaire for use in preparation of the Prospectus
      Supplement and the answers thereto are true and correct as of the date hereof
      and will be true and correct as of the Closing Date, and (c) the Investor,
      in connection with its decision to purchase the number of Units set forth on
      the
      Signature Page, is relying only upon the Disclosure Package, the documents
      incorporated by reference therein and the representations and warranties of
      the
      Company contained herein. 

     

    
      
         

      

      
        -9-

        
          

        

      

      
         

      

    

    8.2     The
      Investor acknowledges, represents and agrees that no action has been or will
      be
      taken in any jurisdiction outside the United States by the Company that would
      permit an offering of the Units, or possession or distribution of offering
      materials in connection with the issue of the Units in any jurisdiction outside
      the United States where action for that purpose is required. Each Investor
      outside the United States will comply with all applicable laws and regulations
      in each foreign jurisdiction in which it purchases, offers, sells or delivers
      Units or has in its possession or distributes any offering material, in all
      cases at its own expense. Agents, officers and employees of the Company are
      not
      authorized to make and have not made any representation or use of any
      information in connection with the issue, placement, purchase and sale of the
      Units, except as set forth or incorporated by reference in the Disclosure
      Package or the Prospectus. 

     

    8.3     The
      Investor further represents and warrants to, and covenants with, the Company
      that (a) the Investor has full right, power, authority and capacity to
      enter into this Agreement and to consummate the transactions contemplated hereby
      and has taken all necessary action to authorize the execution, delivery and
      performance of this Agreement, and (b) this Agreement constitutes a valid
      and binding obligation of the Investor enforceable against the Investor in
      accordance with its terms, except as enforceability may be limited by applicable
      bankruptcy, insolvency, reorganization, moratorium or similar laws affecting
      creditors’ and contracting parties’ rights generally and except as
      enforceability may be subject to general principles of equity (regardless of
      whether such enforceability is considered in a proceeding in equity or at law)
      and except as the indemnification agreements of the Investors herein may be
      legally unenforceable. 

     

    8.4     The
      Investor understands that nothing in this Agreement or any other materials
      presented to the Investor in connection with the purchase and sale of the Units
      constitutes legal, tax or investment advice. The Investor has consulted such
      legal, tax and investment advisors as it, in its sole discretion, has deemed
      necessary or appropriate in connection with its purchase of Units. 

     

    8.5     The
      Investor represents, warrants and agrees that, since the earlier to occur of
      (i) the date on which the Company first contacted the Investor about the
      Offering and (ii) the date that is the tenth (10) trading day prior to
      the date of this Agreement, it has not engaged in any short selling of the
      Company’s securities, or established or increased any “put equivalent position”
as defined in Rule 16(a)-1(h) under the Securities Exchange Act of 1934, as
      amended, with respect to the Company’s securities. 

     

    8.6     The
      Investor represents that, (a) it has had no position, office or other
      material relationship within the past three years with the Company or persons
      known to it to be affiliates of the Company, (b) it is not a NASD member or
      an Associated Person (as such term is defined under the NASD Membership and
      Registration Rules Section 1011) as of the Closing, and (c) neither
      the Investor nor any group of Investors (as identified in a public filing made
      with the Commission) of which the Investor is a part in connection with the
      Offering of the Units, acquired, or obtained the right to acquire, 20% or more
      of the Common Stock (or securities convertible into or exercisable for Common
      Stock) or the voting power of the Company on a post-transaction basis

     

    8.7     The
      Investor represents that it has received, prior to or in connection with the
      receipt of this Agreement, the final Base Prospectus (defined below), which
      is a
      part of the Company’s Registration Statement, and the Prospectus Supplement
      (collectively, the “Disclosure
      Package”)
      along
      with the Company’s counterpart to this Agreement.

     

    9.     The
      completion of the purchase and sale of the Units (the “Closing”)
      will
      occur at a place and time (the “Closing
      Date”)
      to be
      specified by the Company, and of which the Investors will be notified in advance
      by the Company. At the Closing, (a) the Company will cause the Transfer
      Agent to deliver to the Investor the number of Shares (and Units) set forth
      on
      the Signature Page registered in the name of the Investor or, if so indicated
      on
      the Investor Questionnaire attached hereto as Exhibit B,
      in the
      name of a nominee designated by the Investor, (b) the Company shall cause
      to be delivered to the Investor a Warrant to purchase the number of whole
      Warrant Shares determined by multiplying the number of Shares (and Units) set
      forth on the signature page by the Warrant Ratio and rounding up to the nearest
      whole number and (c) the aggregate purchase price for the Units being
      purchased by the Investor will be delivered by or on behalf of the Investor
      to
      the Company.

     

    
      
         

      

      
        -10-

        
          

        

      

      
         

      

    

    9.1     Conditions
      to the Company’s Obligations.
      The
      Company’s obligation to issue the Shares and the Warrants to the Investor will
      be subject to the receipt by the Company of the purchase price for the Units
      being purchased hereunder as set forth on the Signature Page and the accuracy
      of
      the representations and warranties made by the Investor and the fulfillment
      of
      those undertakings of the Investor to be fulfilled prior to the Closing
      Date.

     

    9.2     Conditions
      to the Investor’s Obligations.
      The
      Investor’s obligation to purchase the Units will be subject to the accuracy of
      the representations and warranties made by the Company and the fulfillment
      of
      those undertakings of the Company to be fulfilled prior to the Closing Date
      (collectively, the “Company
      Closing Conditions”).
      The
      Investor’s obligations are expressly not conditioned on the purchase by any or
      all of the Other Investors of the Units that they have agreed to purchase from
      the Company.

     

    10.     The
      executed Warrant shall be delivered in accordance with the terms thereof. The
      executed Warrant shall be delivered in accordance with the terms
      thereof.

     

    11.     The
      manner of settlement of the Shares included in the Units purchased by the
      Investor shall be by delivery by electronic book-entry at The Depository Trust
      Company (“DTC”),
      registered in the Investor’s name and address as set forth below, and released
      by U.S. Stock Transfer, the Company’s transfer agent (the “Transfer
      Agent”),
      to
      the Investor at the Closing. NO
      LATER THAN ONE (1) BUSINESS DAY AFTER THE EXECUTION OF THIS AGREEMENT BY THE
      INVESTOR AND THE COMPANY, THE INVESTOR SHALL: 

     

    
      	 	 	
              (I)

            	
              DIRECT
                THE BROKER-DEALER AT WHICH THE ACCOUNT OR ACCOUNTS TO BE CREDITED
                WITH THE
                SHARES ARE MAINTAINED TO SET UP A DEPOSIT/WITHDRAWAL AT CUSTODIAN
                (“DWAC”)
                INSTRUCTING THE TRANSFER AGENT TO CREDIT SUCH ACCOUNT OR ACCOUNTS
                WITH THE
                SHARES, AND

            

    

     

    
      	 	
              (II)

            	
              REMIT
                BY WIRE TRANSFER THE AMOUNT OF FUNDS EQUAL TO THE AGGREGATE PURCHASE
                PRICE
                FOR THE SHARES BEING PURCHASED BY THE INVESTOR TO THE FOLLOWING
                ACCOUNT:

            

    

    

    Mellon
      Bank

    Pittsburgh,
      PA

    ABA
      #0430-0026-1

    SUB
      ACCT#101-1730

    MERRILL
      LYNCH, PF&S INC.

    Client
      name:  COMBIMATRIX CORPORATION

    Client
      ML
      account #:  68Q-07056

     

    Such
      funds shall be held by the Company until the Closing and satisfaction of the
      Company Closing Conditions. 

     

    Investor
      shall also furnish to the Company a completed W-9 form (or, in the case of
      an
      Investor who is not a United States citizen or resident, a W-8
      form).

     

    12.     Notwithstanding
      any investigation made by any party to this Agreement, all covenants,
      agreements, representations and warranties made by the Company and the Investor
      herein will survive the execution of this Agreement, the delivery to the
      Investor of the Units being purchased and the payment therefor.

     

    13.     All
      notices, requests, consents and other communications hereunder will be in
      writing, will be mailed (a) if within the domestic United States by first-class
      registered or certified airmail, or nationally recognized overnight express
      courier, postage prepaid, or by facsimile or (b) if delivered from outside
      the
      United States, by International Federal Express or facsimile, and will be deemed
      given (i) if delivered by first-class registered or certified mail domestic,
      three business days after so mailed, (ii) if delivered by nationally recognized
      overnight carrier, one business day after so mailed, (iii) if delivered by
      International Federal Express, two business days after so mailed and (iv) if
      delivered by facsimile, upon electric confirmation of receipt and will be
      delivered and addressed as follows:

     

    
      
         

      

      
        -11-

        
          

        

      

      
         

      

    

    (a)    if
      to the
      Company, to: 

     

    Acacia
      Research Corporation

    500
      Newport Center Drive, 7th
      Floor

    Newport
      Beach, California 92660

    Attention:
      Chief Financial Officer

    Phone:
      (949) 480-8300

    Telecopy:
      (949) 480-8301

     

    with
      copies to: 

     

    Greenberg
      Traurig, LLP

    650
      Town
      Center Drive, Suite 1700

    Costa
      Mesa, California 92626

    Attention:
      Raymond A. Lee

    Phone:
      (714) 708-6500

    Telecopy:
      (714) 708-6501 

     

    (b)    if
      to the
      Investor, at its address on the Signature Page hereto, or at such other address
      or addresses as may have been furnished to the Company in writing.

     

    14.     This
      Agreement may not be modified or amended except pursuant to an instrument in
      writing signed by the Company and the Investor.

     

    15.     The
      headings of the various sections of this Agreement have been inserted for
      convenience of reference only and will not be deemed to be part of this
      Agreement.

     

    16.     In
      case
      any provision contained in this Agreement should be invalid, illegal or
      unenforceable in any respect, the validity, legality and enforceability of
      the
      remaining provisions contained herein will not in any way be affected or
      impaired thereby.

     

    17.     This
      Agreement will be governed by, and construed in accordance with, the internal
      laws of the State of New York, without giving effect to the principles of
      conflicts of law that would require the application of the laws of any other
      jurisdiction.

     

    18.     This
      Agreement may be executed in two or more counterparts, each of which will
      constitute an original, but all of which, when taken together, will constitute
      but one instrument, and will become effective when one or more counterparts
      have
      been signed by each party hereto and delivered to the other parties. The Company
      and the Investor acknowledge and agree that the Company shall deliver its
      counterpart to the Investor along with the Prospectus Supplement. 

     

    19.     The
      Investor acknowledges and agrees that such Investor’s receipt of the Company’s
      counterpart to this Agreement, together with the Prospectus Supplement, shall
      constitute written confirmation of the Company’s sale of Shares to such
      Investor.

     

    20.     This
      Agreement shall inure to the benefit of and shall be binding upon the Investors
      and the Company, and their respective successors and assigns. Nothing in this
      Agreement is intended or shall be construed to give to any other person, firm
      or
      corporation, other than the persons, firms or corporations mentioned in the
      preceding sentence, 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 by reason merely of such
      purchase.

     

    IN
      WITNESS WHEREOF,
      the
      Investor and the Company have caused this Securities Purchase Agreement to
      be
      executed by its duly authorized officer as of May 4, 2007.

     

     

    Number
      of
      Units:____________________________ 

     

    Purchase
      Price Per Unit: $0.7375                                      
      

     

    Aggregate
      Purchase Price: $___________________

    

     

    
      
         

      

      
        -12-

        
          

        

      

      
         

      

    

     

    __________________________________

    INVESTOR

     

    By:_______________________________

    Print
      Name:_________________________

    Title:______________________________

    Address:___________________________

    ________________________________________

    ________________________________________

    ________________________________________

     

     

     

    

    ACACIA
      RESEARCH CORPORATION 

    

    

    By:_______________________________

    Name:_____________________________

    Title:______________________________

     

    

    
      
         

      

      
        -13-

        
          

        

      

      
         

      

    

    Exhibit
      A

     

    [FORM
      OF WARRANT]

     

     

    ACACIA
      RESEARCH CORPORATION 

     

    WARRANT
      TO PURCHASE COMMON STOCK

     

    May
      4, 2007

     

    Void
      After May 3, 2012

     

    THIS
      CERTIFIES THAT,
      for
      value received, [             ],
      or
      permitted registered assigns (the “Holder”),
      is
      entitled to subscribe for and purchase at the Exercise Price (defined below)
      from Acacia
      Research Corporation,
      a
      Delaware corporation (the
      “Company”),
      up to
[       ]
      shares
      of
      the Company’s Acacia Research-CombiMatrix common stock, par value $0.001 per
      share (the “Common
      Stock”).

     

    1.     DEFINITIONS.
      As
      used
      herein, the following terms shall have the following respective
      meanings:

     

    (a) “Exercise
      Period” shall mean the period commencing on the date hereof and ending five (5)
      years from the date hereof, unless sooner terminated as provided
      below.

     

    (b) “Exercise
      Price” shall mean $0.55 per share, subject to adjustment pursuant to
      Section 5 below.

     

    (c) “Exercise
      Shares” shall mean the shares of Common Stock issuable upon exercise of this
      Warrant.

     

    (d) “Trading
      Day” shall mean
      (a)
      any day on which the Common Stock is listed or quoted and traded on its primary
      Trading Market, (b) if the Common Stock is not then listed or quoted and traded
      on any Eligible Market, then a day on which trading occurs on the OTC
      Bulletin Board
      (or any
      successor thereto), or (c) if trading does not occur on the OTC Bulletin Board
      (or any successor thereto), any Business Day.

    

    2.     EXERCISE
      OF WARRANT.  The
      rights represented by this Warrant may be exercised in whole or in part at
      any
      time during the Exercise Period, by delivery of the following to the Company
      at
      its address set forth on the signature page hereto (or at such other address
      as
      it may designate by notice in writing to the Holder):

     

    (a) An
      executed Notice of Exercise in the form attached hereto;

    

    (b) Payment
      of the Exercise Price either (i) in cash or by check, (ii) by cancellation
      of
      indebtedness, or (iii) pursuant to Section 2.1 below; and

     

    (c) This
      Warrant.

     

    The
      Holder shall not be required to deliver the original Warrant in order to effect
      the exercise hereunder. Execution and delivery of the Notice of Exercise shall
      have the same effect as cancellation of the original Warrant and issuance of
      a
      new Warrant evidencing the right to purchase the remaining number of Exercise
      Shares.

    

    Certificates
      for shares purchased hereunder shall be transmitted by the transfer agent of
      the
      Company to the Holder by crediting the account of the Holder’s prime broker with
      the  Depository Trust Company through its Deposit Withdrawal Agent
      Commission system if the Company is a participant in such system, and otherwise
      by physical delivery to the address specified by the Holder in the Notice of
      Exercise within three business days from the delivery to the Company of the
      Notice of Exercise, surrender of this Warrant and payment of the aggregate
      Exercise Price as set forth above.  This Warrant shall be deemed to have
      been exercised on the date the Exercise Price is received by the Company. 
The Exercise Shares shall be deemed to have been issued, and Holder or any
      other
      person so designated to be named therein shall be deemed to have become a holder
      of record of such shares for all purposes, as of the date the Warrant has been
      exercised by payment to the Company of the Exercise Price.

     

    
      
         

      

      
        -1-

        
          

        

      

      
         

      

    

    In
      addition to any other rights available to the Holder, if the Company fails
      to
      deliver to the Holder a certificate representing Exercise Shares by the third
      Trading Day after the date on which delivery of such certificate is required
      by
      this Warrant, and if after such third Trading Day the Holder purchases (in
      an
      open market transaction or otherwise) shares of Common Stock to deliver in
      satisfaction of a sale by the Holder of the Warrant Shares that the Holder
      anticipated receiving from the Company (a “Buy-In”),
      then
      in the Holder’s sole discretion, the Company shall within three Trading Days
      after the Holder’s request, either (i) pay cash to the Holder in an amount equal
      to the Holder’s total purchase price (including brokerage commissions, if any)
      for the shares of Common Stock so purchased less the Exercise Price (the
“Buy-In
      Price”),
      at
      which point the Company’s obligation to deliver such certificate (and to issue
      such Common Stock) shall terminate, or (ii) promptly honor its obligation to
      deliver to the Holder a certificate or certificates representing such Common
      Stock and pay cash to the Holder in an amount equal to the excess (if any)
      of
      the Buy-In Price over the product of (A) such number of shares of Common Stock,
      times (B) the Closing Price on the date of the event giving rise to the
      Company’s obligation to deliver such certificate.

     

    The
      person in whose name any certificate or certificates for Exercise Shares are
      to
      be issued upon exercise of this Warrant shall be deemed to have become the
      holder of record of such shares on the date on which this Warrant was
      surrendered and payment of the Exercise Price was made, irrespective of the
      date
      of delivery of such certificate or certificates, except that, if the date of
      such surrender and payment is a date when the stock transfer books of the
      Company are closed, such person shall be deemed to have become the holder of
      such shares at the close of business on the next succeeding date on which the
      stock transfer books are open.

    

    To
      the
      extent permitted by law, the Company’s obligations to issue and deliver Exercise
      Shares in accordance with the terms hereof are absolute and unconditional,
      irrespective of any action or inaction by the Holder to enforce the same, any
      waiver or consent with respect to any provision hereof, the recovery of any
      judgment against any person or entity or any action to enforce the same, or
      any
      setoff, counterclaim, recoupment, limitation or termination, or any breach
      or
      alleged breach by the Holder or any other person or entity of any obligation
      to
      the Company or any violation or alleged violation of law by the Holder or any
      other person or entity, and irrespective of any other circumstance which might
      otherwise limit such obligation of the Company to the Holder in connection
      with
      the issuance of Exercise Shares. Nothing herein shall limit a Holder’s right to
      pursue any other remedies available to it hereunder, at law or in equity
      including, without limitation, a decree of specific performance and/or
      injunctive relief with respect to the Company’s failure to timely deliver
      certificates representing shares of Common Stock upon exercise of the Warrant
      as
      required pursuant to the terms hereof. 

    

    This
      Warrant shall be non-callable.

    

    2.1.     Net
      Exercise. 
If
      during the Exercise Period, the fair market value of one share of the Common
      Stock is greater than the Exercise Price (at the date of calculation as set
      forth below), in lieu of exercising this Warrant by payment of cash or by check,
      or by cancellation of indebtedness, the Holder may elect to receive shares
      equal
      to the value (as determined below) of this Warrant (or the portion thereof
      being
      canceled) by surrender of this Warrant at the principal office of the Company
      together with the properly endorsed Notice of Exercise in which event the
      Company shall issue to the Holder a number of shares of Common Stock computed
      using the following formula:

     

    X
      =
Y
      (A-B)

    A

     

    Where
      X =
      the number of shares of Common Stock to be issued to the Holder

    

    
      	Y
              =	
              the
                number of shares of Common Stock purchasable under the Warrant or,
                if only
                a portion of the Warrant is being exercised, the portion of the Warrant
                being canceled (at the date of such
                calculation)

            

    

      

    
      	
              A
                =
                

            	
              the
                fair market value of one share of the Company’s Common Stock (at the date
                of such calculation)

            

    

     

    
      	
               B
                = 

            	
              Exercise
                Price (as adjusted to the date of such
                calculation)

            

    

     

    For
      purposes of the above calculation, the “fair market value” of one share of
      Common Stock shall mean (i) the average of the closing sales prices for the
      shares of Common Stock on the Nasdaq Global Market or other trading market
      where
      such security is listed or traded as reported by Bloomberg Financial Markets
      (or
      a comparable reporting service of national reputation selected by the Company
      and reasonably acceptable to the Holder if Bloomberg Financial Markets is not
      then reporting sales prices of such security) (collectively, “Bloomberg”) for
      the 10 consecutive trading days immediately preceding such date, or (ii) if
      the
      Nasdaq Global Market is not the principal trading market for the shares of
      Common Stock, the average of the reported sales prices reported by Bloomberg
      on
      the principal trading market for the Common Stock during the same period, or,
      if
      there is no sales price for such period, the last sales price reported by
      Bloomberg for such period, or (iii) if neither of the foregoing applies, the
      last sales price of such security in the over-the-counter market on the pink
      sheets or bulletin board for such security as reported by Bloomberg, or if
      no
      sales price is so reported for such security, the last bid price of such
      security as reported by Bloomberg or (iv) if fair market value cannot be
      calculated as of such date on any of the foregoing bases, the fair market value
      shall be as determined by the Board of Directors of the Company in the exercise
      of its good faith judgment. 

     

    
      
         

      

      
        -2-

        
          

        

      

      
         

      

    

    2.2.     Issuance
      of New Warrants. 
      Upon any partial exercise of this Warrant, the Company, at its expense, will
      forthwith and, in any event within five business days, issue and deliver to
      the
      Holder a new warrant or warrants of like tenor, registered in the name of the
      Holder, exercisable, in the aggregate, for the balance of the number of shares
      of Common Stock remaining available for purchase under the Warrant.

     

    2.3.     Payment
      of Taxes and Expenses. 
      The Company shall pay any recording, filing, stamp or similar tax which may
      be
      payable in respect of any transfer involved in the issuance of, and the
      preparation and delivery of certificates (if applicable) representing, (i)
      any
      Exercise Shares purchased upon exercise of this Warrant and/or (ii) new or
      replacement warrants in the Holder’s name or the name of any transferee of all
      or any portion of this Warrant.

    

    2.4.     Exercise
      Limitations; Holder’s Restrictions.
      A
      Holder shall not have the right to exercise any portion of this Warrant,
      pursuant to Section 2 or otherwise, to the extent that after giving effect
      to
      such issuance after exercise, such Holder (together with such Holder’s
      affiliates), as set forth on the applicable Notice of Exercise, would
      beneficially own in excess of 4.99% of the number of shares of the Common Stock
      outstanding immediately after giving effect to such issuance. For purposes
      of
      the foregoing sentence, the number of shares of Common Stock beneficially owned
      by such Holder and its affiliates shall include the number of shares of Common
      Stock issuable upon exercise of this Warrant with respect to which the
      determination of such sentence is being made, but shall exclude the number
      of
      shares of Common Stock which would be issuable upon (A) exercise of the
      remaining, nonexercised portion of this Warrant beneficially owned by such
      Holder or any of its affiliates and (B) exercise or conversion of the
      unexercised or nonconverted portion of any other securities of the Company
      (including, without limitation, any other shares of Common Stock or Warrants)
      subject to a limitation on conversion or exercise analogous to the limitation
      contained herein beneficially owned by such Holder or any of its affiliates.
      Except as set forth in the preceding sentence, for purposes of this Section
      2.4,
      beneficial ownership shall be calculated in accordance with Section 13(d) of
      the
      Exchange Act, it being acknowledged by a Holder that the Company is not
      representing to such Holder that such calculation is in compliance with Section
      13(d) of the Exchange Act and such Holder is solely responsible for any
      schedules required to be filed in accordance therewith. To the extent that
      the
      limitation contained in this Section 2.4 applies, the determination of whether
      this Warrant is exercisable (in relation to other securities owned by such
      Holder) and of which a portion of this Warrant is exercisable shall be in the
      sole discretion of a Holder, and the submission of a Notice of Exercise shall
      be
      deemed to be each Holder’s determination of whether this Warrant is exercisable
      (in relation to other securities owned by such Holder) and of which portion
      of
      this Warrant is exercisable, in each case subject to such aggregate percentage
      limitation, and the Company shall have no obligation to verify or confirm the
      accuracy of such determination. For purposes of this Section 2.4, in determining
      the number of outstanding shares of Common Stock, a Holder may rely on the
      number of outstanding shares of Common Stock as reflected in (x) the Company’s
      most recent Form 10-Q or Form 10-K, as the case may be, (y) a more recent public
      announcement by the Company or (z) any other notice by the Company or the
      Company’s Transfer Agent setting forth the number of shares of Common Stock
      outstanding. Upon the written or oral request of a Holder, the Company shall
      within two Trading Days confirm orally and in writing to such Holder the number
      of shares of Common Stock then outstanding. In any case, the number of
      outstanding shares of Common Stock shall be determined after giving effect
      to
      the conversion or exercise of securities of the Company, including this Warrant,
      by such Holder or its affiliates since the date as of which such number of
      outstanding shares of Common Stock was reported. The provisions of this Section
      2.4 may be waived by such Holder, at the election of such Holder, upon not
      less
      than 61 days’ prior notice to the Company, and the provisions of this Section
      2.4 shall continue to apply until such 61st
      day (or
      such later date, as determined by such Holder, as may be specified in such
      notice of waiver).

    

    3.     COVENANTS
      OF THE COMPANY.

     

    3.1.     Covenants
      as to Exercise Shares. 
      The Company covenants and agrees that all Exercise 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.  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-

        
          

        

      

      
         

      

    

    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, 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.

     

    3.3.     Notices
      of Record Date and Certain Other Events. 
In
      the event of any taking by the Company of a record of the holders of any class
      of securities for the purpose of determining the holders thereof who are
      entitled to receive any dividend (other than a cash dividend which is the same
      as cash dividends paid in previous quarters) or other distribution, the Company
      shall mail to the Holder, at least 20 days prior to the date on which any such
      record is to be taken for the purpose of such dividend or distribution, a notice
      specifying such date.  In the event of any voluntary dissolution,
      liquidation or winding up of the Company, the Company shall mail to the Holder,
      at least 20 days prior to the date of the occurrence of any such event, a notice
      specifying such date. In the event the Company authorizes or approves, enters
      into any agreement contemplating, or solicits stockholder approval for any
      Fundamental Transaction, as defined in Section 7 herein, the Company shall
      mail
      to the Holder, at least twenty days prior to the date of the occurrence of
      such
      event, a notice specifying such date.

     

    4.     [INTENTIONALLY
      OMITTED]

     

    5.     ADJUSTMENT
      OF
      EXERCISE PRICE AND SHARES.

     

    (a) 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 Exercise Shares subject to this Warrant.

     

    (b) 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, without payment
      therefor,  

     

    (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 5(a) 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 5(a) 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 (including cash in the cases referred to in clauses (ii) and (iii)
      above) 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-

        
          

        

      

      
         

      

    

    (c) Upon
      the
      occurrence of each adjustment pursuant to this Section 5, the Company at its
      expense will, at the written request of the Holder, 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 Exercise Shares or other
      securities issuable upon exercise of this Warrant (as applicable), describing
      the transactions giving rise to such adjustments and showing in 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.

    

    6.     FRACTIONAL
      SHARES.  No
      fractional shares shall be issued upon the exercise of this Warrant as a
      consequence of any adjustment pursuant hereto.  All Exercise 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 shall, 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 an Exercise Share by such fraction.

     

    7.     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) 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 5 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, at the
      option of the Holder, (a) upon exercise of this Warrant, 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.  
      For
      purposes of any such exercise, the determination of the Exercise Price shall
      be
      appropriately adjusted to apply to such Alternate Consideration based on the
      amount of Alternate Consideration issuable in respect of one share of Common
      Stock in such Fundamental Transaction, and the Company shall apportion the
      Exercise Price among the Alternate Consideration in a reasonable manner
      reflecting the relative value of any different components of the Alternate
      Consideration.  If holders of Common Stock are given any choice as to the
      securities, cash or property to be received in a Fundamental Transaction, then
      the Holder shall be given the same choice as to the Alternate Consideration
      it
      receives upon any exercise of this Warrant following such Fundamental
      Transaction.  To the extent necessary to effectuate the foregoing
      provisions, any successor to the Company or surviving entity in such Fundamental
      Transaction shall issue to the Holder a new warrant consistent with the
      foregoing provisions and evidencing the Holder’s right to exercise such warrant
      into Alternate Consideration. The terms of any agreement pursuant to which
      a
      Fundamental Transaction is effected shall include terms requiring any such
      successor or surviving entity to comply with the provisions of this Section
      7
      and insuring that this Warrant (or any such replacement security) will be
      similarly adjusted upon any subsequent transaction analogous to a Fundamental
      Transaction.

     

    8.     NO
      STOCKHOLDER RIGHTS.  This
      Warrant in and of itself shall not entitle the Holder to any voting rights
      or
      other rights as a stockholder of the Company.

     

    9.     TRANSFER
      OF WARRANT.  Subject
      to applicable laws, this Warrant and all rights hereunder are transferable,
      by
      the Holder in person or by duly authorized attorney, upon delivery of this
      Warrant and the form of assignment attached hereto to any transferee designated
      by Holder.

     

    10.    LOST,
      STOLEN, MUTILATED OR DESTROYED WARRANT.  If
      this
      Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms
      as to indemnity or otherwise as it may reasonably impose (which shall, in the
      case of a mutilated Warrant, include the surrender thereof), issue a new Warrant
      of like denomination and tenor as the Warrant so lost, stolen, mutilated or
      destroyed.  Any such new Warrant shall constitute an original contractual
      obligation of the Company, whether or not the allegedly lost, stolen, mutilated
      or destroyed Warrant shall be at any time enforceable by anyone.

     

    
      
         

      

      
        -5-

        
          

        

      

      
         

      

    

    11.    NOTICES,
      ETC.  All
      notices required or permitted hereunder shall be in writing and shall be deemed
      effectively given: (a) upon personal delivery to the party to be notified,
      (b) when sent by confirmed telex or facsimile if sent during normal
      business hours of the recipient, if not, then on the next business day,
      (c) five days after having been sent by registered or certified mail,
      return receipt requested, postage prepaid, or (d) one day after deposit
      with a nationally recognized overnight courier, specifying next day delivery,
      with written verification of receipt.  All communications shall be sent to
      the Company at the address listed on the signature page hereto and to Holder
      at
      the applicable address set forth on the applicable signature page to the
      Subscription Agreement or at such other address as the Company or Holder may
      designate by 10 days advance written notice to the other parties
      hereto.

      

    12.    ACCEPTANCE. 
      Receipt
      of this Warrant by the Holder shall constitute acceptance of and agreement
      to
      all of the terms and conditions contained herein.

     

    13.    GOVERNING
      LAW.  This
      Warrant and all rights, obligations and liabilities hereunder shall be governed
      by the laws of the State of New York.

     

    [REMAINDER
      OF PAGE INTENTIONALLY LEFT BLANK]

     

     

    
      
         

      

      
        -6-

        
          

        

      

      
         

      

    

    IN
      WITNESS WHEREOF,
      the
      Company has caused this Warrant to be executed by its duly authorized officer
      as
      of May 4, 2007.

     

     

    ACACIA
      RESEARCH CORPORATION 

    

    

    

    By:_______________________________

    Name:_____________________________

    Title:______________________________

    

    

    
      
         

      

      
        -7-

        
          

        

      

      
         

      

    

    NOTICE
      OF EXERCISE

     

    TO: 
      ACACIA
      RESEARCH CORPORATION 

     

    (1)    
      ྑ  The
      undersigned hereby elects to purchase
           shares of the
      Acacia Research-CombiMatrix Common Stock (the “Common
      Stock”)
      of
ACACIA
      RESEARCH CORPORATION  (the
      “Company”)
      pursuant to the terms of the attached Warrant, and tenders herewith payment
      of
      the exercise price in full, together with all applicable transfer taxes, if
      any.

     

            
      ྑ  The undersigned hereby elects to purchase
           shares of Common
      Stock of the Company pursuant to the terms of the net exercise provisions set
      forth in Section 2.1 of the attached Warrant, and shall tender payment of
      all applicable transfer taxes, if any.

     

    (2)     Please
      issue a certificate or certificates representing said shares of Common Stock
      of
      the Company in the name of the undersigned or in such other name as is specified
      below:

     

     

    (Name)

     

     

     

    (Address)

     

     

    

            _____________________________

    
      	(Date)	
              (Signature)

            

    

    

    

             _____________________________

            (Print
      name)

     

     

    
      
         

      

      
        
        

        
          

        

      

      
         

      

    

    ASSIGNMENT
      FORM

     

    (To
      assign the foregoing Warrant, execute this form and supply required
      information.  Do not use this form to purchase shares.)

     

    FOR
      VALUE RECEIVED,
      the
      foregoing Warrant and all rights evidenced thereby are hereby assigned
      to

     

    
      	Name:	
              _______________________________

            

    

    (Please
      Print)

     

    
      	Address:	
              _______________________________

            

    

    (Please
      Print)

    

     

    Dated:                          
      , 20___

     

     

      

    Holder’s
      Signature: 

     

    Holder’s
      Address:

     

     

    

     

    

     

     

    NOTE: 
      The signature to this Assignment Form must correspond with the name as it
      appears on the face of the Warrant, without alteration or enlargement or any
      change whatever.  Officers of corporations and those acting in a fiduciary
      or other representative capacity should file proper evidence of authority to
      assign the foregoing Warrant.

     

    
      
         

      

      
        
        

        
          

        

      

      
         

      

    

    Exhibit
      B

     

    ACACIA
      RESEARCH CORPORATION

     

    INVESTOR
      QUESTIONNAIRE

     

    Pursuant
      to the Agreement, please provide us with the following information:

    

    
      	
              1. The
                exact name that your Shares and Warrants are to be registered in.
                You may
                use a nominee name if appropriate:

            	 	 
	 	 	 
	
              2. The
                relationship between the Investor and the registered holder listed
                in
                response to item 1 above:

            	 	 
	 	 	 
	
              3. The
                mailing address of the registered holder listed in response to item
                1
                above:

            	 	 
	 	 	 
	
              4. The
                Social Security Number or Tax Identification Number of the registered
                holder listed in the response to item 1 above:

            	 	 
	 	 	 
	
              5. Name
                of DTC Participant (broker-dealer at which the account or accounts
                to be
                credited with the Shares are maintained):

            	 	 
	 	 	 
	
              6. DTC
                Participant Number:

            	 	 
	 	 	 
	
              7. Name
                of Account at DTC Participant being credited with the
                Shares:

            	 	 
	 	 	 
	
              8. Account
                Number at DTC Participant being credited with the Shares:

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