Copper-catalyzed tandem reaction of ortho-bromobenzamides and isothiocyanates is described, which provides an efficient and practical route for the synthesis of 2-thioxo-2, 3- dihydroquinazolin-4 (1H)-ones. The optimal condition involved the following parameters: CuI as precatalyst, Cs2CO3 as base, N, N′-dimethylethane-1, 2-diamine as ligand, and toluene as solvent, with reaction temperature at 120° C.