We synthesized a novel polymer (2,5-cyclohexadiene-1,4-dione,2,3,5,6-tetradimethyl-,polymer with 4,4'-methylenebis [benzenamine], pTM- CH2) showing a stable one-step successive two-electron transfer (OSTT). We proved the OSTT process of pTM- CH2 using cyclic voltammetry and UV-visible spectroelectrochemistry. When pTM-CH2 (M-w = 328) has a lower molecular weight and higher redox potential (1.18 V vs. NHE) per each two-electron transfer unit compared to polyaniline (PAn), thus produced a rechargeable battery having an energy density (590 Wh/kg) exceeding that of a battery using polyaniline. (c) 2005 The Electrochemical Society.