First, cyclic voltammetry measurements furnished a non-reversible oxidation of DABAl-Me3 with an onset at 0.63 V vs SCE, indicating that excited-state 4CzIPN (E1/2 (PC*/PC •-) = +1.43 V vs SCE) is a suitable oxidant for the methylating reagent (Scheme 4A). After having established the thermodynamic feasibility of DABAl-Me3 reductively quenching excited-state 4CzIPN, we wondered if it is indeed also kinetically feasible. Consequently, Stern-Volmer studies were conducted and showed that DABAl-Me3 quenches the fluorescence of 4CzIPN with a higher efficiency compared to the other reaction components (Scheme 4B). These two findings support the assumption of DABAl-Me3 reductively quenching photo-excited 4CzIPN. In addition, it was experimentally observed that there was a slight pressure build-up towards reaction completion. This prompted us to perform a GC-TCD analysis of these gaseous products (Scheme 4C). As expected, methane was detected which could be formed either via protonation of DABAl-Me3 or H-atom abstraction of CH3CN by the methyl radical. Alongside methane, ethane was detected, whose presence could have resulted from Ni-promoted or direct homocoupling of methyl radicals. To gain further experimental proof for the presence of methyl radical, trapping experiments were conducted (Scheme 4D). The methylation of 1a was attempted in the presence of known radical quenchers 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and 1,1diphenylethylene (DPE). In both cases, the respective adducts were detected by GC-MS, while the product formation was either shut down or vastly suppressed. In addition, EPR measurements were conducted utilizing the spin-trapping reagent DMPO. The reaction was performed under catalytic conditions with an excess of the spin-trapping reagent and an aliquot was analyzed by EPR at room temperature (Scheme 4D). The EPR spectrum shows a signal corresponding to the DMPO-Me persistent radical adduct 38. The simulated parameters of 38 (orange trace, aH = 62.9 MHz, aN = 40.3 MHz) correspond well to the values reported in the literature (Scheme 4E). Taken together, these experiments provide strong evidence for the efficient formation of methyl radicals under the given photocatalytic conditions.