A similar scenario may also apply here as in terms of energy considerations the first excited quartet state becomes only available after excitation into the second prominent absorption band at ca. 400 nm (D 3 ← D 0 ) according to quantum chemical calculations (see Figure and further information in the SI). Performing the model reaction exciting the system into its first electronic absorption band at 680 nm (LED), interestingly, resulted in no product formation (Table , entry 8). However, it is to note, that the available excitation power at 680 nm is lower compared to the power at 400 nm, and, thus, may explain this diminished activity (vide infra). Scope of photocatalytic activity of the photocatalysts. The reactivity in general seems to follow the established pattern for radical cation accelerated arene C-H functionalisation (Figure ). The para selectivity, known for similar systems, indicates that the reactivity occurs via arene oxidation. Various N-nucleophiles such as pyrazoles or purines can be used in the reaction. When A was used as a catalyst, 9% of doubly substituted product was formed. Only small amounts of products were produced from extremely electron poor arenes, like 2-chlorobenzonitriles (see ESI). We also observed nucleophilic C-F substitution (SnAR) for fluorobenzene (Figure ). We envisaged that this reactivity pattern may lead to a significant advantage over existing methods, which use substoichiometric and stoichiometric amounts of unstable and toxic DDQ. Several fluoro-benzenes as well as different trapping reagents could be coupled with moderate to good yields and best performance for electron-rich system. The photocatalyst B allowed activation of even strongly electron deficient arenes, such as 1-chloro-2,4-difluorobenzene. These types of substrates are too electron poor to be oxidized by known photocatalysts, but at the same time they do not undergo thermal SnAR C-F substitution. Reactions were particularly clean, with no side reactions detected. We were also pleased to find that the catalyst can be recovered to 94% after a single cycle.