In a recent advancement (2024), an efficient three-component visible-light-mediated protocol was developed for synthesizing naphtho[2,1-d]thiazol-2-amines 82 by ortho-C-H sulfuration of 2isocyanonaphthalenes 83 with elemental sulfur and amines (Scheme 30) . Remarkably, this reaction proceeded under external photocatalyst-free conditions with an air atmosphere, although potassium persulfate K2S2O8 (1 eq.) was occasionally added as an oxidant. Mechanistic studies suggested that a photoexcited species formed between a DBU-activated thiourea intermediate and visible light drives the reaction. The sequence involves reaction of 2-isocyanonaphthalene 83 with DBU-activated sulfur to yield 2-isothiocyanatonaphthalene 84. Next, nucleophilic attack by an amine to form thiourea 85, and excitation of the thiourea-DBU complex A under visible light to generate an activated species A*. Oxidation of A* by oxygen produces sulfur radical cation B, which deprotonates to yield thiyl radical C. This radical undergoes regioselective intramolecular cyclization to form carbon-centered radical D, which abstracts a hydrogen atom to afford the desired product 82. Scheme 30. Synthesis of naphtho[2,1-d]thiazol-2-amines 82.