Herein, a regioselective bromination or chlorination reaction of 1‐naphthaldehydes is described. Without additive, the palladium‐catalyzed C−H halogenation showed a C8‐regioselectivity, whereas the formation of an aromatic imine intermediate allowed a switch to a C2‐reactivity. Mechanistic studies and DFT calculations were performed to explain the regioselectivity and the synthesized halogenated products were used as key building blocks to access polycyclic natural product skeletons.