The synthon crossover between the halogen⋯π interaction and halogen bonding in a series of N-(4-halophenyl)-2-naphthamide and N-(4-halophenyl)quinoline-2-carboxamide has been investigated by different methods. The results indicate that the heteroatom substitution in the aromatic ring leads to a change in the iodine bonding acceptor site from the iodine atom in N-(4-iodophenyl)-2-naphthamide, naph-I, to the π-electron cloud in N-(4-iodophenyl)quinoline-2-carboxamide, quin-I.