A polythiophene derivative bearing TEMPO radical was synthesized by oxidative chemical polymerization of its monomer. The polymer had a high spin density (2.05 x 10(21) spins/g of polymer). CV studies of the polymer showed that the electrochemical redox reaction of the TEMPO radicals were completely reversible. We demonstrated, for the first time, construction and charge/discharge characteristics of an organic radical battery utilizing a TEMPO bearing polythiophene based cathode material. The battery had an initial specific discharge capacity of 79 A h/kg (87% of the theoretical capacity) and an average output voltage of 3.6 V. The specific energy capacity initially discharged was 268 W h/kg. (C) 2011 Elsevier Ltd. All rights reserved.