Rapid and efficient electrochemical CO2 reduction is an ongoing challenge for the production of sustainable fuels and chemicals. In this work, electrochemical CO2 reduction is investigated using metalloporphyrin catalysts (metal = Mn, Fe, Co, Ni, Cu) that feature one hydroxyphenyl group, and three other phenyl groups, in the porphyrin heterocycle (5-(2-hydroxyphenyl)-10,15,20-triphenylporphyrin, TPOH). These complexes, which are minimal versions of related complexes bearing up to eight proton relays, were designed to allow more straightforward determination of the role of the 2-hydroxylphenyl functional group. The iron-substituted version of TPOH supports robust reduction of CO2 in acetonitrile solvent, where carbon monoxide is the only detected product. Addition of weak Bronsted acids (1 M water or 8 mM phenol) gives rise to almost 100-fold enhancement in turnover frequency. Surprisingly, the iron analogue is a poor catalyst when the solvent is changed to dimethylformamide. These results lead to the proposal of a model where the hydroxyphenyl group behaves as a local proton source, a hydrogen bond donor to CO2-bound intermediates, and a hydrogen bonding partner to Bronsted acids. The observations from this model suggest improvements for existing electrocatalytic CO2 reduction systems.