Interestingly, subjecting the Giese radical addition product 4 to CD-2 under dark conditions did not yield any the cyclization product 55 (Fig. ), indicating that CD-2 lacks acid/base catalytic functionality required to promote cyclization between the aniline N-H and the cyano group (ref . Furthermore, under identical irradiation conditions, the CD-2 photocatalytic system was unable to generate the dehydrogenative cyclization product 34 when 4 was used as the substrate (Fig. ). This observation suggests that the reaction does not proceed through a stepwise mechanism involving stable closed-shell intermediates. Instead, the dehydrogenation step occurs immediately after the radical addition event. This mechanism also accounts for the minor formation of byproduct 4 for CD-2 catalyst, as hydrogen atom rebound competes with and intercepts the pathway leading to 34.