A metal-free, green, and sustainable functionalization of unactivated alkyl sp3 C–H bonds is reported using iodine (III) as a feasible dehydrogenation agent under visible light or KBr, and alkyl chlorides, bromides, alcohols, and ketones could be constructed by addi-tion of different coupling reagents. Cheap and safe iodobenzene diacetate was used to form a strong radical to activate the alkyl sp3 C–H bond in a highly efficient manner, which can construct different alkylation products by adding corresponding coupling reagents.