A concise and versatile method for the construction of unsymmetrical thioureas and oxazolidinethiones from amines and carbon disulfide has been achieved in DMSO without addition of extra reagents. The present protocol is compatible with various secondary amines and primary amines, and suitable for intermolecular and intramolecular reactions. Diverse unsymmetrical thioureas and oxazolidinethiones were efficiently obtained in good to excellent yields via a cascade reaction sequence.