Tetrahydropyridazines constitute an important structural motif found in numerous natural products and pharmaceutical compounds. Herein, we report anaminoacylation reaction of alkenes that enables the synthesis of1,4,5,6-tetrahydropyridazines through cooperative N-heterocyclic carbene (NHC) and photoredox catalysis. This approach involves the6-endo-trigcyclization ofN-centeredhydrazonyl radicals, generated via single-electron oxidation of hydrazones, followed by a radical-radical coupling step.The mild process tolerates a wide range of common functional groups and affords a variety oftetrahydropyridazinesin moderate to high yields. Preliminary investigations using chiral NHC catalysts demonstrate the potential of this protocol for asymmetric radical reactions.