Manganese(III) reagent is an important one- electron oxidant for initiation of free-radical reactions and formation of carbon-carbon bonds. The reactions are usually carried out under mild conditions, have high regio- and stereo-selectivities, and good functional group tolerance. Summarized in this article are the developments of manganese (III)-based reactions for the formation of carbon-heteroatom bonds including carbon-oxygen, carbon-phosphorus, carbon-sulfur, and carbon-nitrogen bonds, and their applications for the synthesis of related heterocyclic systems.