The Grignard metathesis reaction of 2,5-dibromo-3-(5'-hexylpyridine-2'-yl)thiophene (M1) with i-PrMgCl afforded 5-bromo-2-chloromagnesio-3-(5'-hexylpyridine-2'-yl)thiophene (GM1) in the 86% selectivity. The Kumada coupling polymerization by Ni(dppp)Cl-2 gave polyM1 having the roughly controlled molecular weight between 6700 and 23,400. The characterization using the gel permeation chromatographic and matrixassisted laser desorption/ionization-time of flight mass spectra indicated the diffusion of the nickel catalyst from the propagating end. Based on the GC and H-1 NMR spectra, the head-to-tail content of polyM1 was calculated to be 89%. The regioselective Grignard metathesis reactions of 5,5'-dibromo-4-(5 ''-hexylpyridine-2 ''-yl)-2,2'-bithiophene (M2) and 5,5'-dibromo-4-(5 ''-hexyl-pyrimidine-2 ''-yl)-2,2'-bithiophene (M3) also occurred at the ortho-position of the nitrogen heterocycle. The Kumada coupling polymerizations gave polyM2 and polyM3 having the head-to-tail content of 75% and 85%, respectively. The UV-vis spectra of polymers suggested that the polymer conformation becomes more planar in the order of polyM1 < polyM3 < polyM2, which was investigated by the theoretical calculation of the model oligomers. (C) 2014 Wiley Periodicals, Inc.