Synthesis and characterization of reactive intermediates capable of C-H functionalization reactions is central to the rational development of new selective and efficient catalysts. Synthetic photochemistry provides a platform to generate reactive intermediates under conditions in which they can be kinetically trapped, for example by providing a synthetic strategy to generate these species under cryogenic conditions. Application of synthetic photochemistry requires the availability of appropriate photoprecursor molecules and specifically access to photolabile ligands that exhibit predictable photoactivation modes. Here we have advanced N-haloamide ligands as a photolabile ligand in the synthesis of Mn nitrenoids. Isolation of homologous Mn(III) complexes featuring N-chloro-, N-bromo-, and N-iodoamide ligands provided the opportunity to observe the decisive impact of the halogen substituent on the observed photochemistry. Whereas the Mn(III) chloroamide complex undergoes photoreduction via direct homolytic Mn-N activation, the corresponding Mn(III) iodoamide undergoes N-I activation to unveil a reactive Mn nitrenoid that participates in both C-H amination and olefin aziridination chemistry. A combination of lowtemperature spectroscopy and analysis of C-H functionalization kinetic isotope effects indicates the critical photochemical difference between N-chloro-and N-iodoamide ligands. These observations mirror the competition between ligand-centered photoactivation chemistry and photoreduction reactions that are often encountered in the corresponding metal nitride and metal oxo photochemistries. The findings described here begin to delineate the design parameters needed to elicit ligand-centered bond activation to generate metal nitrenoids. We anticipate the development of general strategies in the synthetic photochemistry of metal nitrenoids will expand access to reactive nitrenoids relevant to catalysis, and we are actively working to expand the generality of the haloamide strategies described here.