A Cu-catalyzed relay process for the preparation of diazidated quinazolinone and polycyclic imidazole derivatives in which readily available alkene-tethered substrates undergo an addition/cyclization/C(sp3)-H functionalization of alkene sequences with high efficiency is described. Various functionalized N-heteropolycyclic compounds were readily prepared in good yields with a broad substrate scope. Moreover, the direct azidation of the α-C(sp3)-H bond of the corresponding N-heterocycles has been demonstrated on the basis of mechanistic studies, which provide an alternative late-stage functionalization approach for the derivatization of N-heterocyclic scaffolds.