This review provides an overview of the chemistry of hypervalent organohalogans, organoiodanes and organobromanes, developed recently in Tokushima. Vinylic S_N2 reactions, cyclopentene syntheses via 1,5 C-H insertion of alkylidene carbenes, reductive Claisen rearrangements, oxidations with peroxy-λ³-iodanes, iodobenzene-catalyzed oxidations, oxidative cleavage of double bonds, oxidative coupling of alcohols with alkynes, Michael additions, and transylidations are involved. These reactions mostly rely on the hyperleaving group ability of aryl-λ³-iodanyl, -bromanyl, and -chloranyl groups.