Polymers containing a trans,trans-2,5-thienylenevinylene-1,4-phenylenevinylene moiety were prepared by palladium-catalyzed polycondensation. Couples of 2,5-divinylthiophene derivatives 1 with p-dihalobenzenes 2 successfully produced the expected polymers 5, whereas couples of 2,5-dihalothiophene derivatives 3 with p-divinylbenzene 4 gave only oligomers due to the homo-coupling reaction of 3. Synthesis of a thermotropic liquid crystalline polymer having trans,trans-2,5-distyrylthiophene skeletons as mesogen was also investigated by use of the polycondensation between 1 and bis(p-iodophenyl) compounds 6 that concurrently have flexible segments.