Palladium-catalyzed polymerization of eta(6)-(1,4-diethynylbenzene)tricarbonyl chromium (1) with 3-alkyl-2,5-dibromothiophene (2a-c) was carried out to give the corresponding alternating conjugated copolymers (5a-c) in good yields. The structures of the polymers were supported by H-1 NNM and IR spectra. The polymers obtained were soluble in common solvents such as THF, CH2Cl2, CHCl3 and toluene. The molecular weights of the polymers were determined by GPC. Their thermal, optical and electrical properties were investigated in detail.