As a control, both in the absence of light and a photocatalyst no reactivity was observed (Table , entry 4, 5) demonstrating that the excited radical cation of the photocatalyst is a requirement for photocatalytic activity. Also using the non-cyclic version oB under otherwise identical conditions, resulted in significantly less yield of 19% ( In a recent study, the authors proposed the involvement of higher excited doublet states as a requisite for productive photocatalytic activity allowing for the formation of long-lived quartet states.