A novel method for the synthesis 2,5-bis-substituted-1,3,4-thiadiazoles by direct cyclization of 1,6-bis-substituted dithiourea in refluxing DMF solution is presented. Supramolecular compound 2,5-bis- (ethoxycarbonylamino)-1,3,4-thiadiazole was synthesized via this method, and the structure was determined by elemental analysis, IR, ¹H NMR and X-ray diffraction analysis. Crystal data: monoclinic, space group P2₁/c, a＝1.0093(4) nm，b＝0.9035(4) nm, c＝1.2924(6) nm, β＝96.785(9)°, V＝1.1703(9) nm³, Z＝4, D_c＝1.477 g/cm³, F(000)＝544, μ＝0.287 mm^－1. The su-pramolecule with two-dimensional netlike structure is formed by intermolecular hydrogen bonding.

Key words: synthesis, 1,3,4-thiadiazole, crystal structure