For the synthesis of brush-shaped pi-conjugated polymers having thiophene-based backbones, novel thiophene-end-capped poly(vinyl ether) macromonomers (Th-PMEEVE) were synthesized by living cationic polymerization with a new thiophene-appended initiator. It was found that polycondensation reactions of these macromonomer and 4,7-dibromo-2,1,3-benzothiadiazole (BTDA) via direct arylation reaction afforded the target brush shaped pi-conjugated polymers having a poly(thiophene-alt-BTDA) backbone [poly(Th-PMEEVE-alt-BTDA)].