In this work, we investigated a set of organic mixed ionic-electronic conducting polymers as single-phase electrodes for the oxygen reduction reaction, focusing on p(NDI-T2 P75) as a model system. In p(NDI-T2 P75), the halfwave voltages (E1/2) for the bulk ion-insertion redox reactions (electron polaron formation) and oxygen reduction were found to be independent of pH, and the dominant product was found to be hydro ). For polymers with 𝐸 1 0′ < 𝐸 𝑂 2 /𝑂