Aryl halides are important chemical components in organic syntheses. Herein, we report visible-light-induced, single nickel-catalyzed halogen exchange of aromatic halides with the corresponding halide salts under mild conditions. Varieties of aryl iodides, bromides, and chlorides can smoothly undergo aromatic Finkelstein or retro-Finkelstein reactions with good functional group tolerance. Experimentally, mechanistic studies showed that excited-state NiII complexes for facile reductive elimination to form carbon–halide bonds were involved in the process of Finkelstein and retro-Finkelstein reactions.

Transition-metal-free, sulfur-mediated allylic C–H arylation, epoxidation, and aziridination were realized through one-pot procedures. The reaction design involved initial addition between olefins and triflic anhydride activated sulfoxides, followed by subsequent reactions of the allylic sulfur ylides generated under basic conditions with arylboronic acids, aldehydes, or aldimines, to give allylic arylation, epoxidation, or aziridination products, respectively.

Herein, we report visible light‐promoted single nickel catalysis for diverse carbon–heteroatom couplings under mild conditions. This mild, general, and robust method to couple diverse nitrogen, oxygen, and sulfur nucleophiles with aryl(heteroaryl)/alkenyl iodides/bromides exhibits a wide functional group tolerance and is applicable to late‐stage modification of pharmaceuticals and natural products. On the base of preliminary mechanistic studies, a NiI/NiIII cycle via the generation of active NiI complexes that appear from homolysis of NiII−I rather than NiII−aryl bond was tentatively proposed.