A recent study (2022) explored the cyclization of thiobenzanilides through a blue light-induced (440 nm) photochemical reaction of N,N′-(1,4-aryl)dithioamides 55 in the presence of p-chloranil 14 as a mild oxidizing agent (Scheme 18) . This method enables the selective synthesis of 2,7diarylbenzo[1,2-d:4,3-d′]bis(thiazoles) 56 without generating regioisomeric by-products. The high regioselectivity of the reaction underscores its synthetic utility, and the resulting compounds 56 exhibit intriguing photophysical and (spectro)electrochemical properties. These features highlight their potential applications in the field of organic electronics, offering promising avenues for the development of advanced materials. Halogenated thiobenzanilides 57 can undergo a photocatalyst-and transition-metal-free intramolecular cross-coupling to yield benzothiazoles 58 through a sequence involving absorption, electron transfer, and dehalogenative cyclization (Scheme 19) . Brominated derivatives are predominantly utilized as starting materials, with the corresponding benzothiazoles 58 (R 1 = H, R 2 = Ph) achieved in excellent yields of up to 99%. Other halogens, including iodine, chlorine, and fluorine, afford yields of 99%, 24% and 9%, respectively. Notably, 2-aryl benzothiazoles are synthesized in high yields (90-98%) within 2-10 hours of irradiation. However, 2-alkyl benzothiazoles are obtained in relatively modest yields (41-82%) and require prolonged irradiation of up to 24 hours. Mechanistically, the substrate 57 or its anion A absorbs a photon to form an excited state A*, which undergoes intramolecular electron transfer from the thiolate anion to the N-aryl moiety, generating an intermediate B containing both a thiyl radical and an aryl halide radical anion. This intermediate undergoes debrominative cyclization to yield the final benzothiazole 58 (R 1 = H, R 2 = Ph).