Three new visible‐light‐promoted functionalizations of benzotriazole substrates were discovered using a mechanism‐based screening method. ortho‐Thiolated, borylated, and alkylated N‐arylbenzamide products were obtained under mild reaction conditions in a new denitrogenative synthetic approach to functionalized aniline derivatives. The functional group tolerance of the borylation reaction was further analyzed in the first application of an additive‐based robustness screen in a photocatalytic transformation. All the functionalizations proceed via photocatalytically initiated chain mechanisms as indicated by determination of the reaction quantum yields and Stern–Volmer analyses. Trinity! Three visible‐light‐promoted functionalization reactions of benzotriazole substrates were discovered using a mechanism‐based screening method and provided ortho‐thiolated, ‐borylated, and ‐alkylated N‐arylbenzamide products. The functional group tolerance of the borylation reaction was further analyzed by the first application of an additive‐based robustness screen in a photocatalytic transformation.