Low-valent chromium catalysts are cheap and less toxic compared to other transition metal catalysts. Here in, we reported a ligand-free chromium(III)-catalyzed manganese reductive cross-coupling of unactivated alkyl electrophiles, such as alkyl sulfonates and alkyl chlorides, with trisulfide dioxides as thiolation agents to form carbon-sulfur bonds. The powerful method featured ample substrate scope and wide functional group tolerance, constructing a large number of unsymmetrical disulfides under simple conditions.