Synthesis Energy Systems (SYNE) 10-Q 2015 Q3 Quarterly report

Exhibit 32.1

CERTIFICATION OF PRINCIPAL EXECUTIVE OFFICER

PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906

OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Synthesis Energy Systems, Inc. (the “Company”) on Form 10-Q for the period ended March 31, 2015 (the “Report”), as filed with the Securities and Exchange Commission on the date hereof, I, Robert Rigdon, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

1. The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Robert Rigdon

Robert Rigdon

President and Chief Executive Officer

May 13, 2015