A highly efficient Rh(III)-catalyzed C-H diamidation and diamidation/intramolecular cyclization of N -iminopyridinium ylides with dioxazolones has been developed, providing diamidated products and benzoxazinone products in good to excellent yields. Notably, the tunable selectivity of this reaction can be controlled by simply switching the solvent and the temperature. This reaction features operational simplicity, a broad substrate scope, and a good functional group tolerance.