A series of five new conjugated polythiophene (PT) derivatives containing piperidinyl groups as a side chain were synthesized by ferric trichloride oxidization. All of the polymers were soluble in common organic solvents, and their high regioregularity were confirmed by 1H-NMR. The weight-average molar masses ranged from 5931 to 22,955 g/mol with a low polydispersity index ranging from 1.18 to 1.79. The fluorescence emission maximum of poly[3-(N-methyl propionate4-piperidine)methylenethiophene] in the films was 725 nm in the yellowred region, higher than that of the other PT derivatives. All five polymers exhibited reversible p-doping/dedoping (oxidation/reneutralization) processes; this indicated that these polymers could be applied in electrical equipment in the doping state. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013