Three antimony-based organic–inorganic hybrid perovskites (1,4-3.2.2-H2dabcn)SbX5 (X = Cl, Br, I) show progressively decreasing phase transition temperatures and bandgaps

(X = Cl, Br, I) have been obtained by a halogen substitution strategy, in which an increase in the halogen size (Cl → Br → I) decreases the phase transition temperature (454 K → 343 K) and band gap (2.9 eV → 1.71 eV). With switchable dielectric behavior and tunable semiconductor properties, these materials provide new ideas for the development of smart sensors, nonvolatile memories, and efficient optoelectronic devices.