absorbs more strongly than 4a •+ in this wavelength range. However, the overall TA intensities are low, likely as a result of inefficient cage escape. Given that (i) the ground state of neutral 4a does not absorb above 400 nm and (ii) triplet photoreactions typically proceed with higher quantum yields than singlet reactions, we were looking for a suitable triplet chromophore to obtain a reliable spectrum of 4a •+ in the visible range via reductive quenching upon selective excitation of the triplet sensitizer.