In 2020, Feng and Yang were first who introduced a green method for the phosphorylation of 2isocyanoaryl thioethers via visible-light-induced cascade reactions, employing rose bengal (RB) 19 as a photocatalyst (Scheme 27) . This transition-metal-free process generates C2-phosphorylated benzothiazoles 74 under ambient conditions using aryl-substituted H-phosphorus oxides 75. However, phosphonate esters, such as ethyl, isopropyl, and dicyclohexylphosphine oxides, were unsuitable substrates, resulting in no product formation. Mechanistically, diarylphosphine oxide 75 (Ar = Ph) exists in equilibrium with its phosphinous acid tautomer A. SET from the radical cation ( The generation of phosphorus-centered radicals through interactions with isocyano functional groups has been achieved via cobaloxime photocatalysis (Scheme 28) . Utilizing Co(dmgH)2PyCl 5 as a photocatalyst, triethylamine (TEA) as a base, and dichloromethane (DCM) as a solvent under blue LED irradiation in an argon atmosphere, compounds 76 were synthesized with yields reaching 99%. Notably, similar reactions under sunlight resulted in excellent yields (88-98%) over 21 hours. Mechanistic investigations revealed that photoexcited cobaloxime oxidizes diphenylphosphine oxide to generate a phosphorus radical A and a Co II species. Radical A subsequently adds to (2isocyanophenyl)(methyl)sulfane to form the imidoyl intermediate B, which undergoes intramolecular cyclization, yielding the desired product. The incorporation of alkyl chains into benzothiazole motif through radical addition/cyclization cascades has also been demonstrated. Wang et al. synthesized compound 77 (Scheme 29) using a redox-active ester 78 that forms a photoactive EDA complex with sulfide anions. This anion-πassembled EDA complex, upon visible light absorption, transitions to an excited state and undergoes electron transfer, initiating the reductive decarboxylation to produce a tert-butyl radical. This radical adds to the isocyanide group of (2-isocyanophenyl)(methyl)sulfane, yielding an imidoyl radical, which then cyclizes intramolecularly with concurrent methyl radical release. Worth mentioning, that the substrate scope of this chemistry mainly involved ortho-isocyanobiaryls 79 giving the corresponding 6-alkylphenanthridines, with only compound 77 accessible using this methodology. A similar radical cascade process has been applied using cyclobutanone oxime ester 80 as a precursor (Scheme 29) . Upon photoinduced electron transfer (PET) mediated by a photoredox catalyst like fac-Ir(ppy)3 4, an iminyl radical A is generated, which undergoes selective C-C bond cleavage to form a γcyanoalkyl radical B. This strategy was mainly optimized for aryl isocyanides, although a single example, compound 81, involved an isocyanoaryl thioether. Scheme 29. Synthesis of benzothiazoles 77 and 81.