A thiadiazole derivative, 5-benzylsulfanyl-2-amino-1,3,4-thiadiazole (BSATZ) was prepared. The single crystal structure of BSATZ was determined by X-ray diffraction and the thermal behavior of BSATZ in nitrogen was studied by TG and DSC. Based on the results of thermal analysis, the thermal decomposition mechanism of BSATZ in the temperature range of 100-400 degrees C was derived and the kinetic parameters have also been obtained. The decomposition of BSATZ in this temperature range acts as a model of two-step following reaction of A B F2) C: an nth-order reaction (F-n) with n=2.16, E-1 = 111.59kJmol(-1), 1g(A(1)) (s(-1))=8.82 is followed by a second-order reaction (F-2) with E-2 = 137.16 kJ mol(-1),1g(A(2)) (s(-1)) = 7.15. (c) 2004 Published by Elsevier B.V.