A conducting redox polymer is investigated in acidic electrolyte using various in situ methods, including electron paramagnetic resonance (EPR), UV-vis spectroscopy, and conductance measurements. The quinone redox active pendant group has a formal potential of 0.67 V (vs. standard hydrogen electrode) where a 2e2H process occurs. By analyzing the rate constant at different temperatures, the rate-limiting step in the redox reaction was found to be a thermally activated process with an activation energy of 0.3 eV. The electron transport through the conducting polymer was found to be non-thermally activated and, hence, not redox rate-limiting. This is also the first time a negative temperature dependence has been reported for a conducting redox polymer in the same potential region where the redox active pendant group has its formal potential. EPR and conductance data indicated that the conductivity is governed by both polarons and bipolarons but their ratio is shifting during oxidation and reduction of the polymer. (C) 2019 The Authors. Published by Elsevier Ltd.