Here we report the synthesis and characterization of a family of Mn porphyrins featuring N-haloamide ligands. These complexes are S = 2 species and are fully characterized in both solution phase and the solid state. This family of complexes includes the first examples of Nbromoamide and N-iodoamide complexes of transition metals. Photolysis of these complexes gives rise to the product of C-H amination and olefin aziridination. A combination of kinetic isotope effect analysis and low-temperature spectroscopy indicates that while the photolysis of Mn(III) Nchloroamides proceeds via initial cleavage of the Mn-N bond to generate Mn(II) and amidyl radical intermediates, photolysis of the corresponding N-iodoamide complexes proceeds via N-I cleavage to generate a Mn(IV) nitrenoid that participates in both C-H amination and olefin aziridination. These observations represent the first example of a porphyrin-supported Mn(IV) nitrenoid, highlight the impact of ligand design in the synthesis of novel photoprecursor ligands, and establish N-haloamides as a class of nitrene photoprecursor ligands.