A highly efficient one-pot two-step microwave procedure was developed for the synthesis of 1-aryl-1H-indazoles. Microwave heating of 2-halobenzaldehydes or 2-haloacetophenones with phenylhydrazines at 160° C for 10min quantitatively yielded the arylhydrazones, which were further cyclized to give 1-aryl-1H-indazoles via CuI/diamine-catalyzed N-arylation under microwave heating (160° C, 10min). Good to excellent yields were observed for 2- ...