We believe that the second oxidation of a simple phenylenediamine, H2PD, in the presence of pyridines in acetonitrile provides a nice example of the significant role that step-wise electron-proton transfer within a H-bond intermediate can play. Without added base, the second oxidation corresponds to the reversible one electron oxidation of the radical cation, H2PD+, to the quinoidal dication, H2PD2+. CV data in the presence of one equivalent of pyridines of different basicity result in a significant negative shift in the E1/2 of the second CV wave with no loss in reversibility. Continued addition of the pyridine leads to smaller incremental shifts with still no change in reversibility. Analysis of the observed E1/2’s with one equivalent pyridine as a function of pyridine basicity indicates that, even with the weakest base, proton transfer to the pyridine occurs. This interpretation is supported by spectroelectrochemical data. Thus, the overall reaction occurring in the second CV wave is H2PD+ + B = HPD+ + HB+ + e-, where B is the pyridine base and HB+ is its conjugate acid. The shifts in E1/2 upon further additions of pyridine are nicely predicted by the Nernst equation with this as the overall reaction. However, attempts to simulate the CV data with just PT and ET steps fail at the higher concentrations of pyridine. This is because the rate of the ET step becomes exceedingly slow as the base concentration increases and the thermodynamic potential becomes increasingly removed from the E° of the actual ET step. This issue is simply solved by including in the mechanism the possibility of electron transfer occurring through the H-bond intermediate. This simple change leads to good fits to the experimental data, providing solid support for such a H-bonding intermediate being involved. However, a comparison of experiments with 10:1 cyanopyridine: H2PD run in 2% CH3OH to those run in 2% CD3OD show no significant difference in the ΔEp of the second oxidation, providing no evidence for the oxidation involving CPET. Thus, it appears that ET-PT within the H-bond complex still greatly aids the reversibility of the reaction even without CPET.