Electrochemical and photophysical characterisation of the photocatalysts. The ground state absorption spectra (S n ← S 0 ) as well as the emission spectra of B in ACN are shown in Figure . After exciting electrochemically formed Ar 3 N •+ either at 395 or 740 nm with ca. 100 fs resolution, first the excited Ar 3 N •+ * in its lowest excited state is observed in both cases demonstrating that the higher excited doublet states relax within the temporal resolution (see SI for the electrochemical setup and Figure ). Accordingly and expectedly, no 'anti-Kasha' behaviour is observed as was recently postulated to occur for non-cyclic triarylamine radical cations. In agreement with the expectation, the excited state lifetime of the Ar 3 N •+ * is in the ps temporal range. Interestingly, for both photocatalysts an additional intermediate arises from the excited state decay with a prominent absorption band. The chemical origin of this intermediate is currently not clear, and one may speculate on the formation of an adduct of either H 2 O or O 2 to the excited Ar 3 N •+ . However, this is not further elucidated here, and attempts to identify the nature of this species are currently under investigation in our labs and will be presented elsewhere. To note, when exciting the system at 395 nm into the higher doublet state an additional very faint absorption signal with a band at ca. 490 nm can be observed. As the electrochemically formed Ar 3 N •+ is pumped in circle during the measurement and residual water within the flow system cannot be excluded, this small signal arises from the neutral amine Ar 3 N that will be present in the sample to small amounts.