The polymer complex [Hg(l-mptrz) 2 ] n and two binuclear complexes of {[H 2 en][Hg 2 (mptrz) 4 (l-Br) 2 ]} and {[H 2 en][Hg 2 (mptrz) 4 (l-I) 2 ]} were prepared from the reaction of 4-methyl-1,2,4-triazole-3-thiol (Hmptrz) and ethylene diamine (en) with HgCl 2 , HgBr 2 , and HgI 2 in CH 3 OH, respectively. Complex [Hg(l-mptrz) 2 ] n was also prepared from the reaction of 4-methyl-1,2,4-triazole-3-thiol and ethylene diamine with Hg(OAc) 2 and Hg(SCN) 2 in CH 3 OH and Hg(NO 3 ) 2 ÁH 2 O in a mixture of CH 3 OH/ H 2 O. Analysis of these complexes was done by CHN elemental analysis, IR, UV-Vis, 1 H and 13 C NMR, and luminescence spectroscopy, as well as single-crystal X-ray diffraction. Thermal stabilities of these complexes were also studied by TGA/DTA analyses.