Interestingly, the observed spectrum can reasonably account for some of the inconsistencies between the ns-TA spectrum and that of Ir(IV) in the spectroelectrochemistry difference spectrum, in particular in the spectral region at λ = ~ 430 nm where Ni(I) shows strongest absorbance. As such, the spectroelectrochemical data supports assignment of the species contributing to the ns-TA signal at t = 10 µs as Ir(IV) and Ni(I). Control experiments support that no species aside from Ni (i.e. free ligand, K2CO3, aryl halide, or alcohol) quenches [Ir(ppy)3]* significantly (See SI, Section 3.4). In addition, this reduction is electrochemically feasible based on cyclic voltammetry data (E[Ir(III)*/Ir(IV)] = ─1.66 V vs. SCE; E[Ni(II)/Ni(I)] = ─1.23 V vs. SCE, See SI, Table ). The PhenO PC is also highly reducing (E[ 1 PhenO*/PhenO •+ ] = ─1.73 V vs. SCE), and ns-TA experiments conducted here support that it also engages with Ni-OMebpy complexes via an oxidative quenching pathway (See SI, Section 3.5). This finding raises the broader possibility that any PC with a sufficiently reducing excited state might engage with Ni(II) via oxidative quenching.