Table . Optimization of e-PRC C-H heteroamination using Generation 2 TPAs. Interestingly, under the same applied constant potential Ucell as in Table and in contrast to the use of TpBPA, here toluene underwent benzylic oxidation instead of amination, while a pyrazole-4-carboxaldehyde (either before or after benzene C-H amination) underwent oxidation to its carboxylic acid (Table , bottom). Bromobenzene gave a lower yield of 3fb than that in Table . The above observations indicate a less oxidizing TPA .+ excited state (such as that from TpBPA .+ ) is beneficial for certain substrates and demonstrates the value of tunability presented by this class of e-PRCats. We further probed the limits of arene SET oxidations with TCBPA .+ , by targeting 1,2-dichlorobenzene and trifluorotoluene, and were encouraged to detect products, albeit in low yields, from each when using TCBPA (17% of 3jb and 7%, respectively). Yields did not increase with extended reaction time (96 h) or higher applied potential (Ucell = +1.8 V), which suggested that we had reached the oxidizing limit of this photoexcited TPA .+ . Gratifyingly, further e-PRCat tuning in the form of the even more electron-deficient tris(2',4'-dicyano-[1,1'-biphenyl]-4-yl)amine (TdCBPA) increased the yield of 3jb to a much more satisfactory 31% (Table ). Although polyfluorinated arenes were activated to afford 3ob and 3hb in only modest yields (~20%), it should be emphasized that oxidative SNAr-type activation of such challenging substrates with pyrazoles has not to our knowledge been previously accomplished. In An intriguing theme running through the TPA-mediated e-PRC substrate scope is the apparent influence of steric effects on reactivity. In contrast to a previous report and in line with the trends observed in Table , product yields increased as a function of the substitution pattern on dichloroarenes (1,4-< 1,3-≤ 1,2-dichlorobenzene). This was surprising, given the corresponding increasing order of E p ox (1,4-< 1,2-≤ 1,3-dichlorobenzene).