Zhang and co-workers reported the cyclization of 2-isocyanoaryl thioethers 66 to synthesize 2-CF₃/2-CF₂-containing benzothiazoles 67, 68 using fac-Ir(ppy)₃ 4 as a photocatalyst, with either the Umemoto reagent or ethyl 2-bromo-2,2-difluoroacetate as the fluoroalkyl source (Scheme 23) . Unlike conventional methodologies employing tertiary amines as reductants for SET processes, sodium sulfite (Na₂SO₃) was utilized to regenerate Ir³⁺ from Ir⁴⁺, enabling fluoroalkylation under mild reaction conditions. Mechanistically, visible-light irradiation of fac-Ir(ppy)₃ 4 produces its excited state (fac-Ir*(ppy)₃), which undergoes SET with ethyl 2-bromo-2,2-difluoroacetate to yield the CF₂COOEt radical A and Ir⁴⁺. Radical A then reacts with the isonitrile group in the substrate, forming the imidoyl radical intermediate B. Subsequent intramolecular cyclization by the benzylthio moiety generates the target product 68 (R 1 = H) and benzyl radical. Concurrently, Ir⁴⁺ is reduced back to Ir³⁺ by Na₂SO₃, completing the catalytic cycle. The benzyl radical can undergo oxidation by Ir⁴⁺ to form a benzyl cation, which reacts with bromide (Br⁻) to generate benzyl bromide or dimerizes to yield 1,2diphenylethane by-product. In the absence of Na₂SO₃, the benzyl radical is predominantly oxidized to the benzyl cation, which may react with isonitrile to form cation intermediates C and D. These intermediates undergo intramolecular nucleophilic attack, ultimately producing benzyl bromide and a benzothiazole by-product 69. . This methodology employs commercially available perfluoroalkyl iodides (e.g., ICnF2n+1, n = 3-8, 10, ICF(CF3)2, ICF2COOEt, ICF2CF2Cl, or ICF2CF2Br), tetramethylethane-1,2-diamine (TMEDA), and visiblelight irradiation, eliminating the need for external photocatalysts. The reaction is initiated by the formation of an EDA complex between perfluoroalkyl iodide and TMEDA. Visible-light irradiation of this complex generates perfluoroalkyl radicals (Rf • ), TMEDA⁺ • radical cation, and iodide ions (I⁻). Radical Rf • reacts with the isonitrile group in the starting material, yielding the imidoyl radical intermediate A, which undergoes intramolecular cyclization to form sulfonium radical B. Two mechanistic pathways are proposed. In the first pathway, B undergoes SET with TMEDA⁺ • , forming sulfonium cation C. A nucleophilic attack by iodide on C produces the target product 71 (R 1 = H) and methyl iodide (MeI), which reacts with TMEDA to generate a quaternary ammonium salt. Alternatively, in the second possible pathway, B undergoes a proton-coupled electron transfer (PCET) with TMEDA⁺ • , yielding the target product 71 (R 1 =H) and iminium ion D, along with methane formation.