A [4 + 1] cyclization and C-C bond cleavage process mediated reaction for constructing 3-carbonyl imidazo[1,5-a] pyridines from 1,3-dicarbonyl compounds and pyridin-2-ylmethanamines has been developed. Various 1,3-dicarbonyl compounds are applicable, and selectivity could be achieved. Importantly, this strategy could be extended to an atom economy method by employing a cyclic 1,3-dicarbonyl compound, and it provided a new view for C-C bond cleavage reactions.