Three novel poly[3-(p-substituted)benzoyl-2,5-thiophene]s (Ib, IIb, and IIIb) were successfully prepared via nickel(0)-catalyzed coupling polymerization of 3-benzoyl-2,5-dichlorothiophene (Ia), 3-(p-fluoro)benzoyl-2,5-dicklorothiophene (IIa), and 3-(p-toluoyl)-2,5-dichlorothiophene (IIIa). To our knowledge, monomers (IIa) and (IIIa) are new compounds. On the basis of K and a values from the Mark-Houwink relationship, the [M-v] of the polymers were in the range 1.50 x 10(5) to 3.51 x 105 g/mol. The a value equal to 0.97 is close to unity indicating that the [M-v] is approximately equal to the [M-w]. The high molecular weight polymers were soluble in common organic solvents. Their glass transition temperatures were all above 160 degrees C and showed no evidence of crystallinity by differential scanning calorimetry. All three polymers were thermally and thermooxidatively stable with 10% weight loss in nitrogen and air occurring above 430 degrees C. The UV-vis absorption lambda(max) for the three polymers greater than 465 nm is a further evidence of the high molecular weight and the long effective conjugation length.