), there are other factors limiting oxygen reduction, namely conductivity. Still, in this case there is no requirement for catalytic adsorption and oxygen reduction may proceed through the outer-sphere mechanism. and UV-Vis spectroscopy revealed that there is a direct chemical reaction between the polaronic state of the polymer and oxygen, forming a reduced oxygen species and re-oxidizing the polymer to the neutral state in the process (i.e. an electron transfer process mediated by the polymer). To rationalize these observations, we investigate the O2 adsorption energetics of p(NDI-T2 P75) at different redox states and potential binding sites (Figure ) using density functional theory (DFT) to. A full description of the DFT calculation methods is provided in the Supplementary Information.