A square-planar, iridium(l) carbene complex is shown to effect atom and group transfer from nitrous oxide and organic azides, releasing the corresponding formate or formimidate and an iridium (I)-dinitrogen adduct. The dinitrogen complex performs C-H activation upon photolysis or thermolysis, regenerating the carbene from tert-butyl methyl ether with loss of H-2. Taken together, these reactions represent a net catalytic cycle for C-H functionalization by double C-H activation to generate metal-carbon multiple bonds. Additionally, the unusual group transfer from diazo reagents underscores the unique nature of the reactivity observed for nucleophilic-at-metal carbene complexes.