Exhibit 4.1





 


WARRANT AGREEMENT


 


This Warrant Agreement
made as of December 7, 2016, is between ClearSign Combustion Corporation, a Washington corporation, with offices at 12870 Interurban
Avenue South, Seattle, Washington 98168 (the “Company”), and VStock Transfer, LLC, with offices at 18 Lafayette Place,
Woodmere, New York (the “Warrant Agent”).


 


WHEREAS, the Company is
engaged in a shareholder rights offering and an offering, on a best efforts, no minimum basis, through a placement agent (collectively
the “Offering”) of units consisting of shares of common stock of the Company, par value $0.0001 per share (“Common
Stock”), and warrants to purchase shares of Common Stock of the Company and, in connection therewith, has determined to issue
and deliver up to 2,594,082 Warrants to shareholders and investors (collectively, the “Investors”) who purchase
the Units in the Offering, each such Warrant evidencing the right of the holder thereof to purchase one share of Common Stock for
$4.00 per share (“Warrant Price”), subject to adjustment as described herein (the “Warrants”);


 


WHEREAS,
the Company has filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form
S-3 (File No. 333-208784, the “Registration Statement”) (as the same may be amended from time to time) for the
registration, under the Securities Act of 1933, as amended, of the shares of Common Stock and the Warrants to be sold to Investors
in the Offering and the shares of Common Stock underlying the Warrants (the “Warrant Shares”);


 


WHEREAS, the Company desires
the Warrant Agent to act on behalf of the Company, and the Warrant Agent is willing to so act, in connection with the issuance,
registration, transfer, exchange, redemption and exercise of the Warrants;


 


WHEREAS, the Company desires
to provide for the form and provisions of the Warrants, the terms upon which they shall be issued and exercised, and the respective
rights, limitation of rights and immunities of the Company, the Warrant Agent and the holders of the Warrants (each, a “Record
Holder”) or if the Warrants are held in “street name”, a Participant (as defined below) or a designee appointed
by such Participant; and


 


WHEREAS, all acts and things
have been done and performed which are necessary to make the Warrants, when executed on behalf of the Company and countersigned
by or on behalf of the Warrant Agent, as provided herein, the legally valid and binding obligations of the Company, and to authorize
the execution and delivery of this Warrant Agreement.


 


NOW, THEREFORE, in consideration
of the mutual agreements herein contained, the parties hereto agree as follows:


 


1.          Appointment
of Warrant Agent. The Company hereby appoints the Warrant Agent to act as agent for the Company for the Warrants, and the Warrant
Agent hereby accepts such appointment and agrees to perform the same in accordance with the terms and conditions set forth in this
Agreement.


 




     


     


    

 


2.           Warrants.


 


2.1         Form
of Warrant. Each Warrant shall be (a) issued in registered form only, (b) in substantially the form of Exhibit A attached
hereto, the provisions of which are incorporated herein, (c) signed by, or bear the facsimile signature of, the Chairman of the
Board or, the Chief Executive Officer or the President, and the Treasurer, Secretary or Assistant Secretary of the Company, and
(d) signed by the Warrant Agent. In the event the person whose facsimile signature has been placed upon any Warrant shall have
ceased to serve in the capacity in which such person signed the Warrant before such Warrant is issued, it may be issued with the
same effect as if he or she had not ceased to be such at the date of issuance. All of the Warrants shall initially be represented
by one or more book-entry certificates (each, a “Book-Entry Warrant Certificate”).


 


2.2         Effect
of Countersignature. Unless and until countersigned by the Warrant Agent pursuant to this Agreement, a Warrant shall be invalid
and of no effect and may not be exercised by the holder thereof. Warrant certificates shall be dated the date of countersignature
by the Warrant Agent.


 


2.3         Registration.


 


2.3.1           Warrant
Register. The Warrant Agent shall maintain books (the “Warrant Register”) for the registration of the original
issuance and the registration of transfer of the Warrants. Upon the initial issuance of the Warrants, the Warrant Agent shall issue
and register the Warrants in the names of the respective holders thereof in such denominations and otherwise in accordance with
instructions delivered to the Warrant Agent by the Company. To the extent the Warrants are eligible for the book entry and depository
services of The Depository Trust Company (“DTC Eligible”) as of the date of issuance (the “Issuance Date”),
all of the Warrants shall be represented by one or more Book-Entry Warrant Certificates deposited with The Depository Trust Company
(“Depository”) and registered in the name of Cede & Co., a nominee of the Depository. Ownership of beneficial interests
in the Book-Entry Warrant Certificates shall be shown on, and the transfer of such ownership shall be effected through, records
maintained (i) by the Depository or its nominee for each Book-Entry Warrant Certificate; (ii) by institutions that have accounts
with the Depository (such institution, with respect to a Warrant in its account, a “Participant”); or (iii) directly
on the book-entry records of the Warrant Agent with respect only to owners of interests represented by such direct registration.
If the Warrants are not DTC Eligible as of the Issuance Date or the Depository subsequently ceases to make its book-entry settlement
system available for the Warrants, DTC will instruct the Warrant Agent regarding making other arrangements for book-entry settlement
within 10 days after the Depository ceases to make its book-entry settlement available. In the event that DTC does not make alternative
arrangements for book-entry settlement within 10 days or the Warrants are not eligible for, or it is no longer necessary to have
the Warrants available in, book-entry form, the Warrant Agent shall provide written instructions to the Depository to deliver to
the Warrant Agent for cancellation each Book-Entry Warrant Certificate, and DTC shall instruct the Warrant Agent to deliver to
the Depository definitive certificates (“Warrant Certificates”) in physical form evidencing such Warrants. Such Warrant
Certificates shall be in substantially the form annexed hereto as Exhibit A.


 




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2.3.2           Beneficial
Owner; Record Holder. The term “beneficial owner” shall mean any person in whose name ownership of a beneficial
interest in the Warrants evidenced by a Book-Entry Warrant Certificate is recorded in the records maintained by the Depository
or its nominee. Prior to due presentment to the Warrant Agent for registration of transfer of any Warrant, the Company and the
Warrant Agent may deem and treat the person in whose name such Warrant is registered in the Warrant Register as the absolute owner
of such Warrant and of each Warrant represented thereby (notwithstanding any notation of ownership or other writing on the Warrant
Certificate (as defined below) made by anyone other than the Company or the Warrant Agent), for the purpose of any exercise thereof,
and for all other purposes, and neither the Company nor the Warrant Agent shall be affected by any notice to the contrary.


 


2.3.3           Uncertificated
Warrants. Notwithstanding the foregoing and anything else herein to the contrary, the Warrants may be issued in uncertificated
form.


 


3.           Terms
and Exercise of Warrants.


 


3.1         Warrant
Price. Each Warrant shall, when countersigned by the Warrant Agent, entitle the Record Holder thereof, subject to the provisions
of such Warrant and of this Warrant Agreement, to purchase from the Company the number of shares of Common Stock and at the price,
subject to the adjustments provided in Section 4 hereof. The term “Warrant Price” as used in this Warrant Agreement
refers to the price per share at which Common Stock may be purchased at the time a Warrant is exercised. 


 


3.2         Duration of Warrants. A Warrant may be exercised only during the period
(“Exercise Period”) commencing on the date of issuance and ending on January 25, 2019 (“Expiration Date”).
Each Warrant not exercised on or before the Expiration Date shall become void, and all rights thereunder and all rights in respect
thereof under this Agreement shall cease at 5:00 p.m. Eastern time on the Expiration Date.


 


3.3         Exercise
of Warrants. 


 


3.3.1           Payment.
Subject to the provisions of the Warrant and this Warrant Agreement, a Warrant, when countersigned by the Warrant Agent, may be
exercised by the Record Holder thereof by surrendering it, at the office of the Warrant Agent, or at the office of its successor
as Warrant Agent, with the Election to Purchase, as set forth in the Warrant, duly executed, and by paying to the Company in full,
in lawful money of the United States, in cash, good certified check or good bank draft payable to the order of the Company (or
as otherwise agreed to by the Company), the Warrant Price for each full share of Common Stock as to which the Warrant is exercised
and any and all applicable taxes due in connection with the exercise of the Warrant, the exchange of the Warrant for the Common
Stock, and the issuance of the Common Stock. No ink-original Election to Purchase shall be required, nor shall any medallion guarantee
(or other type of guarantee or notarization) of any Election to Purchase form be required; provided, however, that
if the Company’s transfer agent is not participating in the Depository’s Fast Automated Securities Transfer Program
and the Record Holder requests that the shares of Common Stock be issued or registered to a holder other than the Record Holder,
then an ink-original Election to Purchase and a medallion guarantee shall be required. The Record Holder shall not be required
to deliver the original Warrant in order to effect an exercise hereunder. In no event shall the Record Holder of any Warrant be
entitled to “net cash settle” the Warrant.


 




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3.3.2           Issuance
of Certificates. Assuming funds for exercise of the Warrant are paid on or before the second Trading Day following the date
of receipt by the Warrant Agent of the Election to Purchase and that the Registration Statement, including the Prospectus, or another
registration statement and current prospectus, covering the Warrants and the Warrant Shares is effective, then on or before the
third Trading Day following the date upon which the Company has received the Warrant Price, the Company shall cause its transfer
agent to (i) provided that the transfer agent is participating in the Depository’s Fast Automated Securities Transfer
Program, credit such aggregate number of shares of Common Stock to which the Holder is entitled pursuant to such exercise to the
Holder’s or its designee’s balance account with the Depository through its Deposit/Withdrawal at Custodian System,
or (ii) if the transfer agent is not participating in the Depository’s Fast Automated Securities Transfer Program, issue
and deliver to the Holder, or at the Holder’s instruction pursuant to the delivered Election to Purchase, the Holder’s
agent or designee, in each case pursuant to this clause (ii), sent by reputable overnight courier to the address specified in the
applicable Election to Purchase, a certificate, registered in the Company’s share register in the name of the Holder or its
designee (as indicated in the applicable Election to Purchase), for the number of shares of Common Stock to which the Holder is
entitled pursuant to such exercise. While any Warrants remain outstanding, the Company shall maintain a transfer agent that participates
in the Depository’s Fast Automated Securities Transfer Program. “Trading Day” means any day that the primary
trading market on which the Common Stock is listed or quoted is open for trading.”


 


3.3.3           Valid
Issuance. All shares of Common Stock issued upon the proper exercise or surrender of a Warrant in conformity with this Agreement
shall be validly issued, fully paid and nonassessable.


 


3.3.4           Date
of Issuance. Each person in whose name any certificate for the Common Stock is issued or to whom shares of Common Stock are
credited to such person’s account at the Depository shall for all purposes be deemed to have become the holder of record
of such Common Stock as of the time that a duly executed Election to Purchase is delivered in accordance with Section 3.3.1, assuming
payment of the Warrant Price is made within two Trading Days after the delivery of the Election to Purchase, and if the payment
of the Warrant Price is not made within two Trading Days after the delivery of the Election to Purchase, the Holder shall be deemed
to have become the holder of record of such Common Stock on the first Trading Day after the date on which the Warrant Price has
been paid, irrespective of the date of delivery of such certificate or the date the shares of Common Stock are credited to such
person’s account at the Depository, except that, if the date of such delivery and/or 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.


 


4.           Adjustments.


 


4.1         Events
Requiring Adjustment. The Warrant Price and number of Warrant Shares issuable upon exercise of this Warrant are subject to
adjustment from time to time as set forth in this Section 4.


 




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4.1.1.          Stock
Dividends; Subdivisions; Combinations. If the Company, at any time while the Warrants are outstanding, (i) pays a stock dividend
on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock,
(ii) subdivides its outstanding shares of Common Stock into a larger number of shares of Common Stock, (iii) combines its outstanding
shares of Common Stock into a smaller number of shares of Common Stock or (iv) issues by reclassification of shares of capital
stock any additional shares of Common Stock of the Company, then in each such case the Warrant Price shall be multiplied by a fraction,
the numerator of which shall be the number of shares of Common Stock outstanding immediately before such event and the denominator
of which shall be the number of shares of Common Stock outstanding immediately after such event. Any adjustment made pursuant to
clause (i) of this paragraph shall become effective immediately after the record date for the determination of shareholders entitled
to receive such dividend or distribution, provided, however, that if such record date shall have been fixed and such dividend is
not fully paid on the date fixed therefor, the Warrant Price shall be recomputed accordingly as of the close of business on such
record date and thereafter the Warrant Price shall be adjusted pursuant to this Section as of the time of actual payment of such
dividends. Any adjustment pursuant to clause (ii) or (iii) of this Section shall become effective immediately after the effective
date of such subdivision or combination.


 


4.1.2           Property
Distributions. If the Company, at any time while the Warrants are outstanding, distributes to all holders of Common Stock for
no consideration (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the
preceding paragraph) or (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case,
“Distributed Property”), then, upon any exercise of this Warrant that occurs after the record date fixed for determination
of stockholders entitled to receive such distribution, the Holder shall be entitled to receive, in addition to the Warrant Shares
otherwise issuable upon such exercise (if applicable), the Distributed Property that such Holder would have been entitled to receive
in respect of such number of Warrant Shares had the Holder been the record holder of such Warrant Shares immediately prior to such
record date without regard to any limitation on exercise contained therein.


 


4.1.3           Fundamental
Transactions. If, at any time while the Warrants are outstanding (i) the Company effects any merger or consolidation of the
Company with or into another Person, in which the Company is not the surviving entity or the shareholders of the Company immediately
prior to such merger or consolidation do not own, directly or indirectly, at least 50% of the voting power of the surviving entity
immediately after such merger or consolidation, (ii) the Company effects any sale to another Person of all or substantially all
of its assets in one or a series of related transactions, (iii) pursuant to any tender offer or exchange offer (whether by the
Company or another Person), holders of capital stock who tender shares representing more than 50% of the voting power of the capital
stock of the Company and the Company or such other Person, as applicable, accepts such tender for payment, (iv) the Company consummates
a stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off
or scheme of arrangement) with another Person whereby such other Person acquires more than the 50% of the voting power of the capital
stock of the Company or (v) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant
to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (other than as a result
of a subdivision or combination of shares of Common Stock covered by Section 4.1.1 above) (in any such case, a “Fundamental
Transaction”), then following such Fundamental Transaction the Holder shall have the right to receive, upon exercise of this
Warrant, the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence
of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of the number of
Warrant Shares then issuable upon exercise in full of the Warrant without regard to any limitations on exercise contained herein
(the “Alternate Consideration”). The Company shall not effect any Fundamental Transaction in which the Company is not
the surviving entity or the Alternate Consideration includes securities of another Person unless prior to or simultaneously with
the consummation thereof, any successor to the Company, surviving entity or other Person (including any purchaser of assets of
the Company) shall assume the obligation to deliver to the Holder such Alternate Consideration as, in accordance with the foregoing
provisions, the Holder may be entitled to receive, and the other obligations under this Warrant. “Person” means any
natural person, corporation, firm, joint venture, partnership, limited liability company, association, enterprise, trust or other
entity or organization, or any government or political subdivision or any agency, department or instrumentality thereof.


 




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4.1.4           Adjustment
to Number of Warrant Shares. Simultaneously with any adjustment to the Warrant Price pursuant to Section 4.1.1, the number
of Warrant Shares that may be purchased upon exercise of this Warrant shall be increased or decreased proportionately, so that
after such adjustment the aggregate Warrant Price payable hereunder for the increased or decreased number of Warrant Shares shall
be the same as the aggregate Warrant Price in effect immediately prior to such adjustment.


 


4.1.5           Method
of Calculation. All calculations under this Section 4 shall be made to the nearest cent or the nearest whole share, as the
case may be. For purposes of this Section 4, any calculation of the number of shares of Common Stock deemed to be issued and outstanding
as of a given date shall not include treasury shares, if any. Notwithstanding anything to the contrary in this Section 4, no adjustment
in the Warrant Price shall be required unless such adjustment would require an increase or decrease of at least 1% in such price;
provided, however, that any adjustments which by reason of the immediately preceding sentence are not required to be made shall
be carried forward and taken into account in any subsequent adjustment.


 


4.1.6           Notification
at the Request of Holder. Upon the occurrence of each adjustment pursuant to this Section 4, the Company at its expense will,
at the written request of the Holder, promptly compute such adjustment, in good faith, in accordance with the terms of the Warrant
and prepare a certificate setting forth such adjustment, including a statement of the adjusted Warrant Price and adjusted number
or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions
giving rise to such adjustments and showing in 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.


 




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4.1.7           Notice
to Holder and Warrant Agent. If, while this Warrant is outstanding, the Company (i) declares a dividend or any other distribution
of cash, securities or other property in respect of its Common Stock, including, without limitation, any granting of rights or
warrants to subscribe for or purchase any capital stock of the Company or any subsidiary or (ii) authorizes or approves or enters
into any material definitive agreement contemplating any Fundamental Transaction or (iii) authorizes, approves or solicits stockholder
approval for any Fundamental Transaction, including authorizing the voluntary dissolution, liquidation or winding up of the affairs
of the Company, then, except if such notice and the contents thereof shall be deemed to constitute material non-public information,
the Company shall deliver to the Holder and to the Warrant Agent a notice of such transaction at least 10 days prior to the applicable
record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such
transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of
the corporate action required to be described in such notice. In addition, if while this Warrant is outstanding, the Company enters
into any material definitive agreement contemplating, or solicits, stockholder approval for any Fundamental Transaction contemplated
by Section 4.1.3, other than a Fundamental Transaction under clause (iii) of Section 4.1.3, the Company shall deliver to the Holder
and to the Warrant Agent a notice of such Fundamental Transaction at least 15 days prior to the date such Fundamental Transaction
is consummated. Failure to give such notice, or any defect therein, shall not affect the legality or validity of such event.


 


4.1.8           No
Fractional Shares. Notwithstanding any provision contained in this Warrant Agreement to the contrary, the Company shall not
issue fractional shares upon exercise of Warrants. If, by reason of any adjustment made pursuant to this Section 4, the holder
of any Warrant would be entitled, upon the exercise of such Warrant, to receive a fractional interest in a share, the Company
shall, upon such exercise, round down to the nearest whole number the number of the shares of Common Stock to be issued to the
Warrant holder.


 


4.1.9           Form
of Warrant. The form of Warrant need not be changed because of any adjustment pursuant to this Section 4, and Warrants issued
after such adjustment may state the same Warrant Price and the same number of shares as is stated in the Warrants initially issued
pursuant to this Agreement. However, the Company may, at any time, in its sole discretion, make any change in the form of Warrant
that the Company may deem appropriate and that does not affect the substance thereof, and any Warrant thereafter issued or countersigned,
whether in exchange or substitution for an outstanding Warrant or otherwise, may be in the form as so changed.


 


5.           Transfer
and Exchange of Warrants.


 


5.1           Registration
of Transfer. The Warrant Agent shall register the transfer, from time to time, of any outstanding Warrant into the Warrant
Register, upon surrender of such Warrant for transfer, properly endorsed with signatures properly guaranteed and accompanied by
appropriate instructions for transfer. Upon any such transfer, a new Warrant representing an equal aggregate number of Warrants
shall be issued and the old Warrant shall be cancelled by the Warrant Agent. The Warrants so cancelled shall be delivered by the
Warrant Agent to the Company from time to time upon the Company’s request.


 


5.2           Procedure
for Surrender of Warrants. Warrants may be surrendered to the Warrant Agent, together with a written request for exchange or
transfer, and, thereupon, the Warrant Agent shall issue in exchange therefor one or more new Warrants as requested by the Record
Holder of the Warrants so surrendered, representing an equal aggregate number of Warrants; provided, however, that, in the event
a Warrant surrendered for transfer bears a restrictive legend, the Warrant Agent shall not cancel such Warrant and shall issue
new Warrants in exchange therefor until the Warrant Agent has received an opinion of counsel for the Company stating that such
transfer may be made and indicating whether the new Warrants must also bear a restrictive legend.


 




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5.3           Fractional
Warrants. The Warrant Agent shall not be required to effect any registration of transfer or exchange which will result in the
issuance of a warrant certificate for a fraction of a warrant.


 


5.4           Warrant
Execution and Countersignature. The Warrant Agent is hereby authorized to countersign and to deliver, in accordance with the
terms of this Agreement, the Warrants required to be issued pursuant to the provisions of this Section 5, and the Company, whenever
required by the Warrant Agent, will supply the Warrant Agent with Warrants duly executed on behalf of the Company for such purpose.


 


6.           Other
Provisions Relating to Rights of Holders of Warrants.


 


6.1           No
Rights as Stockholder. A Warrant does not entitle the Record Holder thereof to any of the rights of a stockholder of the Company,
including, without limitation, the right to receive dividends, or other distributions, exercise any preemptive rights to vote or
to consent or to receive notice as stockholders in respect of the meetings of stockholders or the election of directors of the
Company or any other matter.


 


6.2           Lost,
Stolen Mutilated or Destroyed Warrants. If any Warrant is lost, stolen, mutilated or destroyed, the Company and the Warrant
Agent may, on such terms as to indemnity or otherwise as they may in their discretion impose (which terms shall, in the case of
a mutilated Warrant, include the surrender thereof), issue a new Warrant of like denomination, tenor and date as the Warrant so
lost, stolen, mutilated or destroyed. Any such new Warrant shall constitute a substitute contractual obligation of the Company,
whether or not the allegedly lost, stolen, mutilated or destroyed Warrant shall be at any time enforceable by anyone.


 


6.3           Reservation
of Common Stock. The Company shall at all times reserve and keep available a number of its authorized but unissued shares of
Common Stock that will be sufficient to permit the exercise in full of all outstanding Warrants issued pursuant to this Warrant
Agreement.


 


6.4           Registration
of Common Stock. The Company registered the Warrants and the Warrant Shares in the Registration Statement. The Company will
use its reasonable best efforts to maintain the effectiveness of the Registration Statement and the current status of the Prospectus
or to file and maintain the effectiveness of another registration statement and another current prospectus covering the Warrants
and the Warrant Shares at any time that the Warrants are exercisable. In addition, the Company agrees to use its reasonable best
efforts to register the Warrants and Warrant Shares under the blue sky laws of the states of residence of the Record Holders to
the extent an exemption from such registration is not available.


 




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7.           Concerning
the Warrant Agent and Other Matters. 


 


7.1           Payment
of Taxes. The Company will, from time to time, promptly pay all taxes and charges that may be imposed upon the Company or the
Warrant Agent in respect of the issuance or delivery of shares of Common Stock upon the exercise of Warrants, but the Company shall
not be obligated to pay any transfer taxes in respect of the Warrants or such shares.


 


7.2         Resignation,
Consolidation, or Merger of Warrant Agent.


 


7.2.1           Appointment
of Successor Warrant Agent. The Warrant Agent, or any successor to it hereafter appointed, may resign its duties and be discharged
from all further duties and liabilities hereunder after giving 60 days’ notice in writing to the Company. If the office of
the Warrant Agent becomes vacant by resignation or incapacity to act or otherwise, the Company shall appoint, in writing, a successor
Warrant Agent in place of the Warrant Agent. If the Company shall fail to make such appointment within a period of thirty (30)
days after it has been notified in writing of such resignation or incapacity by the Warrant Agent or by the holder of the Warrant
(who shall, with such notice, submit his, her or its Warrant for inspection by the Company), then the holder of any Warrant may
apply to the Supreme Court of the State of New York for the County of New York for the appointment of a successor Warrant Agent.
Any successor Warrant Agent, whether appointed by the Company or by such court, shall be a corporation organized and existing under
the laws of the State of New York, in good standing and have its principal office in the Borough of Manhattan, City and State of
New York, and be authorized under such laws to exercise corporate trust powers and be subject to supervision or examination by
federal or state authorities. After appointment, any successor Warrant Agent shall be vested with all the authority, powers, rights,
immunities, duties and obligations of its predecessor Warrant Agent with like effect as if originally named as Warrant Agent hereunder,
without any further act or deed; but, if for any reason it becomes necessary or appropriate, the predecessor Warrant Agent shall
execute and deliver, at the expense of the Company, an instrument transferring to such successor Warrant Agent all the authority,
powers, and rights of such predecessor Warrant Agent hereunder; and, upon request of any successor Warrant Agent, the Company shall
make, execute, acknowledge, and deliver any and all instruments in writing for more fully and effectually vesting in and confirming
to such successor Warrant Agent all such authority, powers, rights, immunities, duties and obligations.


 


7.2.2           Notice
of Successor Warrant Agent. In the event a successor Warrant Agent shall be appointed, the Company shall give notice thereof
to the predecessor Warrant Agent and the transfer agent for the Common Stock not later than the effective date of any such appointment.



 


7.2.3           Merger
or Consolidation of Warrant Agent. Any corporation into which the Warrant Agent may be merged or with which it may be consolidated
or any corporation resulting from any merger or consolidation to which the Warrant Agent shall be a party shall be the successor
Warrant Agent under this Warrant Agreement without any further act on the part of the Company or the Warrant Agent.


 




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7.3         Fees
and Expenses of Warrant Agent.


 


7.3.1           Remuneration.
The Company agrees to pay the Warrant Agent reasonable remuneration for its services as Warrant Agent hereunder as set forth
on Exhibit B hereto and will reimburse the Warrant Agent upon demand for all expenditures that the Warrant Agent may reasonably
incur in the execution of its duties hereunder.


 


7.3.2           Further
Assurances. The Company agrees to perform, execute, acknowledge and deliver, or cause to be performed, executed, acknowledged
and delivered, all such further and other acts, instruments and assurances as may reasonably be required by the Warrant Agent for
the carrying out or performing of the provisions of this Warrant Agreement.


 


7.4         Liability
of Warrant Agent.


 


7.4.1           Reliance
on Company Statement. Whenever, in the performance of its duties under this Warrant Agreement, the Warrant Agent shall deem
it necessary or desirable that any fact or matter be proved or established by the Company prior to taking or suffering any action
hereunder, such fact or matter (unless other evidence in respect thereof be herein specifically prescribed) may be deemed to be
conclusively proved and established by a statement signed by the Chief Executive Officer, Chief Financial Officer or Chairman of
the Board of the Company and delivered to the Warrant Agent. The Warrant Agent may rely upon such statement for any action taken
or suffered in good faith by it pursuant to the provisions of this Warrant Agreement.


 


7.4.2           Indemnity.
The Warrant Agent shall be liable hereunder only for its own negligence, willful misconduct or bad faith. The Company agrees to
indemnify the Warrant Agent and save it harmless against any and all liabilities, including judgments, costs and reasonable counsel
fees, for anything done or omitted by the Warrant Agent in the execution of this Warrant Agreement, except as a result of the Warrant
Agent’s negligence, willful misconduct or bad faith.


 


7.4.3           Exclusions.
The Warrant Agent shall have no responsibility with respect to the validity of this Warrant Agreement or with respect to the validity
or execution of any Warrant (except its countersignature thereof); nor shall it be responsible for any breach by the Company of
any covenant or condition contained in this Warrant Agreement or in any Warrant; nor shall it be responsible to make any adjustments
required under the provisions of Section 4 hereof or responsible for the manner, method or amount of any such adjustment or the
ascertaining of the existence of facts that would require any such adjustment; nor shall it, by any act hereunder, be deemed to
make any representation or warranty as to the authorization or reservation of any shares of Common Stock to be issued pursuant
to this Warrant Agreement or any Warrant or as to whether any shares of Common Stock will when issued be valid and fully paid
and nonassessable.


 


7.5           Acceptance
of Agency. The Warrant Agent hereby accepts the agency established by this Warrant Agreement and agrees to perform the same
upon the terms and conditions herein set forth and, among other things, shall account promptly to the Company with respect to Warrants
exercised and concurrently account for, and pay to the Company, all moneys received by the Warrant Agent for the purchase of shares
of the Company’s Common Stock through the exercise of Warrants.


 




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8.           Miscellaneous
Provisions.


 


8.1           Successors.
All the covenants and provisions of this Warrant Agreement by or for the benefit of the Company or the Warrant Agent shall bind
and inure to the benefit of their respective successors and assigns.


 


8.2           Notices.
Any notice, statement or demand authorized by this Warrant Agreement to be given or made by the Warrant Agent or by the holder
of any Warrant to or on the Company shall be delivered by hand or sent by registered or certified mail or overnight courier service,
addressed (until another address is filed in writing by the Company with the Warrant Agent) as follows:


 


ClearSign Combustion Corporation


12870 Interurban Avenue South


Seattle Washington 98168


Attn: James N. Harmon,
Chief Financial Officer


 


Any notice, statement or demand authorized
by this Warrant Agreement to be given or made by the holder of any Warrant or by the Company to or on the Warrant Agent shall be
delivered by hand or sent by registered or certified mail or overnight courier service, addressed (until another address is filed
in writing by the Warrant Agent with the Company), as follows:


 


VStock Transfer, LLC

18 Lafayette Place

Woodmere, NY 11598

Attn: Warrant Department


 


Any notice, sent pursuant to this Warrant Agreement
shall be effective, if delivered by hand, upon receipt thereof by the party to whom it is addressed, if sent by overnight courier,
on the next business day of the delivery to the courier, and if sent by registered or certified mail on the third day after registration
or certification thereof


 


8.3           Applicable
Law. The validity, interpretation, and performance of this Warrant Agreement and of the Warrants shall be governed in all respects
by the laws of the State of New York, without giving effect to conflict of laws. The Company hereby agrees that any action, proceeding
or claim against it arising out of or relating in any way to this Warrant Agreement shall be brought and enforced in the courts
of the State of New York or the United States District Court for the Southern District of New York, and irrevocably submits to
such jurisdiction, which jurisdiction shall be exclusive. The Company hereby waives any objection to such exclusive jurisdiction
and that such courts represent an inconvenient forum. Any such process or summons to be served upon the Company may be served by
transmitting a copy thereof by registered or certified mail, return receipt requested, postage prepaid, addressed to it at the
address set forth in Section 8.2 hereof. Such mailing shall be deemed personal service and shall be legal and binding upon the
Company in any action, proceeding or claim.


 




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8.4         Examination of the Warrant Agreement. A copy of this Warrant Agreement shall
be available at all reasonable times at the office of the Warrant Agent for inspection by the Record Holder of any Warrant. The
Warrant Agent may require any such holder to submit his, her or its Warrant for inspection.


 


8.5         Counterparts-
Facsimile Signatures. This Warrant Agreement may be executed in any number of counterparts, and each of such counterparts shall,
for all purposes, be deemed to be an original, and all such counterparts shall together constitute one and the same instrument.
Facsimile signatures shall constitute original signatures for all purposes of this Warrant Agreement.


 


8.6         Effect
of Headings. The section headings herein are for convenience only and are not part of this Warrant Agreement and shall not
affect the interpretation thereof 


 


8.7         Amendments.


 


8.7.1           This
Agreement and any Warrant certificate may be amended by the parties hereto by executing a supplemental warrant agreement (a “Supplemental
Agreement”), without the consent of any of the Warrant holders, for the purpose of (i) curing any ambiguity, or curing,
correcting or supplementing any defective provision contained herein, or making any other provisions with respect to matters or
questions arising under this agreement that is not inconsistent with the provisions of this agreement or the Warrant certificates,
(ii) evidencing the succession of another corporation to the Company and the assumption by any such successor of the covenants
of the Company contained in this agreement and the Warrants, (iii) evidencing and providing for the acceptance of appointment by
a successor Warrant Agent with respect to the Warrants, (iv) adding to the covenants of the Company for the benefit of the holders
or surrendering any right or power conferred upon the Company under this Agreement, or (v) amending this Agreement and the Warrants
in any manner that the Company may deem to be necessary or desirable and that will not adversely affect the interests of the Warrant
holders in any material respect.


 


8.7.2           The
Company and the Warrant Agent may amend this Warrant Agreement and the Warrants by executing a Supplemental Agreement with the
consent of the holders of not fewer than a majority of the unexercised Warrants affected by such amendment, for the purpose of
adding any material provisions to or changing in any material manner or eliminating any of the material provisions of this Agreement
or of modifying in any manner the rights of the holders under this Warrant Agreement; provided, however, that, without the consent
of each of the Warrant holders affected thereby, no such amendment may be made that (i) changes the Warrants so as to reduce the
number of shares purchasable upon exercise of the Warrants or so as to increase the Warrant Price (other than as provided
by Section 4), (ii) shortens the period of time during which the Warrants may be exercised, (iii) otherwise adversely affects the
exercise rights of the holders in any material respect, or (iv) reduces the number of unexercised Warrants the holders of which
must consent for amendment of this Agreement or the Warrants.


 


8.8         Severability.
This Warrant Agreement shall be deemed severable, and the invalidity or unenforceability of any term or provision hereof shall
not affect the validity or enforceability of this Warrant Agreement or of any other term or provision hereof. Furthermore, in lieu
of any such invalid or unenforceable term or provision, the parties hereto intend that there shall be added as a part of this Warrant
Agreement a provision as similar in terms to such invalid or unenforceable provision as may be possible and be valid and enforceable.


 


[SIGNATURES APPEAR ON NEXT
PAGE]


 




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IN WITNESS WHEREOF, this Warrant
Agreement has been duly executed by the parties hereto as of the day and year first above written.


 


	 	CLEARSIGN COMBUSTION CORPORATION
	 	 	 
	 	By: 	/s/ James N. Harmon
	 	 	James N. Harmon, Chief Financial Officer
	 	 
	 	VSTOCK TRANSFER, LLC
	 	 	 
	 	By:	/s/ Yoel Goldfeder
	 	 	Yoel Goldfeder, Chief Executive Officer


 




    	 	13	 



     


    

 


EXHIBIT A


 


Form of Warrant


 


[FORM OF WARRANT CERTIFICATE] 


 


Number


 


Warrants 


 


THIS WARRANT SHALL BE VOID IF NOT EXERCISED
PRIOR TO 


 


THE EXPIRATION OF THE EXERCISE PERIOD PROVIDED
FOR


 


IN THE WARRANT AGREEMENT DESCRIBED BELOW


 


CLEARSIGN COMBUSTION CORPORATION


 


Incorporated Under the Laws of the State
of Washington


 


CUSIP 185064110


 


Warrant Certificate 


 


This Warrant Certificate
certifies that __________________, or its registered assigns, is the record holder of warrant(s) (the “Warrants” and
each, a “Warrant”) to purchase shares of Common Stock, $0.0001 par value per share (“Common Stock”), of
ClearSign Combustion Corporation, a Washington corporation (the “Company”). Each Warrant entitles the
holder, upon exercise during the period set forth in the Warrant Agreement referred to below, to receive from the Company that
number of fully paid and nonassessable shares of Common Stock as set forth below, at the exercise price (the “Exercise Price”)
as determined pursuant to the Warrant Agreement, payable in lawful money of the United States of America, subject to the conditions
set forth herein and in the Warrant Agreement. Defined terms used in this Warrant Certificate but not defined herein shall have
the meanings given to them in the Warrant Agreement (as defined on the reverse hereof).


 


Each Warrant is initially
exercisable for one fully paid and non-assessable share of Common Stock. The number of shares of Common Stock issuable upon exercise
of the Warrants is subject to adjustment upon the occurrence of certain events set forth in the Warrant Agreement.


 


The initial Exercise Price
per share of Common Stock for any Warrant is equal to $4.00 per share. The Exercise Price is subject to adjustment upon the occurrence
of certain events set forth in the Warrant Agreement.


 


Subject to the conditions
set forth in the Warrant Agreement, the Warrants may be exercised only during the Exercise Period, which commences on the date
of issuance and ends on January 25, 2019, and to the extent not exercised by the end of such Exercise Period, such Warrants shall
become void.


 


Reference is hereby made
to the further provisions of this Warrant Certificate set forth on the reverse hereof and such further provisions shall for all
purposes have the same effect as though fully set forth at this place.


 




    	 	14	 



     


    

 


This Warrant Certificate
shall not be valid unless countersigned by the Warrant Agent, as such term is used in the Warrant Agreement.


 


This Warrant Certificate
shall be governed by and construed in accordance with the internal laws of the State of New York, without regard to conflicts of
laws principles thereof.


 




    	 	15	 



     


    

 


IN WITNESS WHEREOF, the parties hereto
have caused this Warrant Certificate to be duly executed as of the date first above written.


 


	 	CLEARSIGN COMBUSTION CORPORATION
	 	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:
	 	 
	 	VSTOCK TRANSFER, LLC as Warrant Agent
	 	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:


 


[Signature Page to Warrant Certificate]


 




    	 	16	 



     


    

 


[Form of Warrant Certificate] 


 


[Reverse] 


 


The Warrants evidenced
by this Warrant Certificate are part of a duly authorized issue of Warrants entitling the holder on exercise to receive shares
of Common Stock and are issued or to be issued pursuant to a Warrant Agreement dated as of December 7, 2016 (the “Warrant
Agreement”), duly executed and delivered by the Company to VStock Transfer, LLC, a California limited liability
trust company, as warrant agent (the “Warrant Agent”), which Warrant Agreement is hereby incorporated
by reference in and made a part of this instrument and is hereby referred to for a description of the rights, limitation of rights,
obligations, duties and immunities thereunder of the Warrant Agent, the Company and the holders (the words “holders”
or “holder” meaning the Record Holders or Record Holder) of the Warrants. A copy of the Warrant Agreement may be obtained
by the holder hereof upon written request to the Company. Defined terms used in this Warrant Certificate but not defined herein
shall have the meanings given to them in the Warrant Agreement.


 


Warrants may be exercised
at any time during the Exercise Period, which commences on the date of issuance and ends on January 25, 2019, as set forth in Section
3.2 of the Warrant Agreement.


 


The Warrant Agreement
provides that upon the occurrence of certain events the number of shares of Common Stock issuable upon exercise of the Warrants
set forth on the face hereof may, subject to certain conditions, be adjusted. If, upon exercise of a Warrant, the holder thereof
would be entitled to receive a fractional interest in a share of Common Stock, the Company shall, upon exercise, round down to
the nearest whole number of shares of Common Stock to be issued to the holder of the Warrant.


 


Warrant Certificates,
when surrendered at the principal corporate trust office of the Warrant Agent by the Record Holder thereof in person or by legal
representative or attorney duly authorized in writing, may be exchanged, in the manner and subject to the limitations provided
in the Warrant Agreement, but without payment of any service charge, for another Warrant Certificate or Warrant Certificates of
like tenor evidencing in the aggregate a like number of Warrants.


 


Upon due presentation
for registration of transfer of this Warrant Certificate at the office of the Warrant Agent, a new Warrant Certificate or Warrant
Certificates of like tenor and evidencing in the aggregate a like number of Warrants shall be issued to the transferee(s) in exchange
for this Warrant Certificate, subject to the limitations provided in the Warrant Agreement, without charge except for any tax or
other governmental charge imposed in connection therewith.


 


The Company and the Warrant
Agent may deem and treat the Record Holder(s) hereof as the absolute owner(s) of this Warrant Certificate (notwithstanding any
notation of ownership or other writing hereon made by anyone), for the purpose of any exercise hereof, of any distribution to the
holder(s) hereof, and for all other purposes, and neither the Company nor the Warrant Agent shall be affected by any notice to
the contrary. Neither the Warrants nor this Warrant Certificate entitles any holder hereof to any rights of a stockholder of the
Company.


 




    	 	17	 



     


    

 


Election to Purchase 


 


(To Be Executed Upon Exercise of Warrant)



 


The undersigned hereby
irrevocably elects to exercise the right, represented by this Warrant Certificate, to receive shares of Common Stock and herewith
tenders payment for such shares to the order of ClearSign Combustion Corporation (the “Company”) in the amount of $__________________
in accordance with the terms hereof. The undersigned requests that a certificate for such shares be registered in the name of _____________________________,
whose address is ______________________________________________________________, and that such shares be delivered to ______________________________,
whose address is ______________________________________________________________________. If said number of shares is less than
all of the shares of Common Stock purchasable hereunder, the undersigned requests that a new Warrant Certificate representing the
remaining balance of such shares be registered in the name of ______________________________________________, whose address is
______________________________________________________, and that such Warrant Certificate be delivered to ____________________________________________,
whose address is _______________________________________________________________.


 


Date: ____________________________________


 


	 	 
	 	 
	 	 
	 	Print Name
	 	 	 
	 	Address:	 
	 	 
	 	 
	 	 
	 	 
	 	Tax Identification Number


 







    	 	18	 



     


    

 


EXHIBIT B


 


Warrant Agent Fees


 


Monthly Maintenance Fee


 


Our monthly maintenance fee is calculated based upon the number
of record shareholders per class or series of Warrants:


 


		o	Monthly Maintenance of 1-99 Registered Holder  $99 per month



		o	Monthly Maintenance of 100-200 Registered Holder        $150 per month



		o	Monthly Maintenance of 200-300 Registered Holder        $299 per month



		o	Monthly Maintenance of 300-500 Registered Holder        $399 per month



		o	Monthly Maintenance of 500+ Registered Holder  $749 per month



 


Service Fees


 


The following are a sample of services provided on a per transaction
fee basis as set forth below:


 


	 	o	Per Warrant Exercise	$45.00
	 	o	Issuance Per Warrant	$35.00 
	 	o	Replacement of Lost or Stolen Warrant	$50.00 (paid by Registered Holder)
	 	o	Lost Registered Holder search (if needed)	$5.00 per Registered Holder per search
	 	o	Escheatment (if needed)	$50.00 per Registered Holder


 


Other Costs and Excluded Services


 


The company will be billed separately at cost
for certain out-of-pocket expenses such as postage and courier fees.


 




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