We, herein, describe a copper-mediated domino CuAAC intramolecular selanylation for the synthesis of unprecedented fused benzo[4,5][1,3]selenazolo[3,2-c][1,2,3]triazoles from 1,2-bis(2-azidoaryl)diselenides and terminal alkynes under microwave irradiation. This is the seminal method for the synthesis of these fused heterocycles, and it proceeds under mild conditions, tolerates several functional groups, and can be carried out using environmentally benign solvents such as dimethyl carbonate. This transformation has been successfully extended to TMS-protected alkynes and to bioactive alkynes. A plausible reaction mechanism is proposed based on several control experiments and previous reports.