We present a novel, eco-friendly and one-pot approach for synthesizing unsymmetrical oxalamide with the aid of dichloroacetamide and amine/amides in the presence of CBr4 under a basic medium. The use of water as a potent supplement for the oxygen atom source and the detailed mechanism have been disclosed.  Moreover, the protocol involves triple cleavage of CCl2Br and the formation of new C-O/C-N bonds, with the advantage of achieving selective bromination using CBr4 with good to excellent yield under mild conditions. The method also demonstrates promise for industrial use, as proven by its effective implementation in gram-scale synthesis conducted in a batch process, along with its utilization in a continuous-flow system.