Comparisons of the UV-visible spectra of TPA .+ revealed a plausible explanation; that TpBPA benefitted from the strongest absorption at 400 nm. Decreasing LED input power by ca. 10x decreased the yield (entry 5). Screening of other protic sources revealed MeOH to be most effective (entry 6). Carbon foam was a superior anodic WE to carbon felt, likely due to its higher surface area (entries 6-7). Gratifyingly, screening of other CE materials revealed copper to be the optimal cathodic CE (entries 8-9). A decreased TpBPA loading (5%) gave an inferior (but still high) yield (entry 10) and LiClO4 as an electrolyte was inferior (entry 11). While DMF as solvent gave no reaction, we were surprised the reaction performed well in DCM as solvent, despite its lower conductivity (entries 12-13). The yield of 3aa tracked well with increasing applied constant potential (Figure ). For full optimization studies, see the Supplementary Information. With optimal conditions in hand, the amination of arenes with a variety of pharmaceutically-relevant N-heterocycles was explored (Table ). Halide-bearing and carbonyl (aldehyde, ketone and ester)-bearing pyrazoles, triazole, benzotriazole, and a functionalized derivative of benzimidazole afforded generally good to excellent (50-89%) yields of aminated mesitylenes 3aa-3aj. We note that benzimidazole derivatives have not been reported as nucleophiles in previous photoelectrochemical arene amination or conPET photocatalytic methods. 6-Chloro-2-fluoropurine afforded a modest yield of 3ak (32%), presumably due to its steric hinderance as a nucleophile. Xylenes and toluene were tolerated to afford aminated arenes 3bb-3fb in moderate to excellent (30-88%) yields.