Poly[di(2,5-dimercapto-1.,3,4-thiadiazole)]-metal complexes of Co(II), Ni(II), Cu(II), and Zn(II) were synthesized by the reaction of 2,5-dimercapto-1,3,4-thiadiazole (6.6 mmol) with anhydrous cobalt, nickel, copper, and zinc chlorides (3.3 mmol) in absolute ethanol under reflux for 24 h. The products were characterized by elemental analyses, electronic spectra, FTIR spectroscopy, as well as thermal analyses (TGA and DTA), and X-ray diffraction. The DC electrical conductivity variation of the poly [di(2,5-dimercapto-1,3,4-thiadiazole)metal] complexes were studied in the temperature range 300-500 K as annealed for 24 h at 100 degrees C and after doping with 5% 12 for comparison. An attempt is made to interpret the DC electrical conductivity behavior and thermal properties to doping, annealing, structure, and metal used. (c) 2007 Wiley Periodicals.