A new triple cooperative and relay catalysis system featuring the Mannich addition followed by C–C construction and oxydehydrogenation is described. The zirconocene dichloride and trimellitic acid synergic catalysis triggered the Mannich addition and C–C bond construction reactions, while CuO allowed relay catalysis for oxydehydrogenation. This novel strategy demonstrated superior activity for the
quinoline-4-carboxylates, while iron-promoted cascade amino Claisen rearrangement, aromatization, and aza-Michael addition afford diverse 2-substituted indole-3-carboxylate derivatives. Excellent selectivity, broad functional group tolerance, mild conditions, and flexible late-stage functionalization illustrate the high efficiency and synthetic utility of this chemodivergent reaction.