A new hybrid organic–inorganic perovskite, ( R-3AQ)KI3 [ R-3AQ2+ = ( R)-(+)-3-aminoquinuclidine], has been synthesized and comprehensively characterized by experimental approaches and density functional theory calculations. Our experimental results demonstrate that ( R-3AQ)KI3 has a typical perovskite structure and exhibits a reversible order–disorder phase transition at temperatures of 457 and 443 K on heating and cooling, respectively. Under ultraviolet irradiation, a clear yellowish-green emission peaked at 556 nm was observed for ( R-3AQ)KI3. The calculated electronic structure shows that ( R-3AQ)KI3 possesses a typical direct bandgap with a value of 3.74 eV and its valence band maximum and conduction band minimum primarily arise from the I-5p and I-5s orbitals, respectively. In addition, the elastic calculations indicate that ( R-3AQ)KI3 displays a relatively large structure stiffness, relatively small elastic anisotropy, and fairly low acoustic velocity, owing to the rigid K–I bonds and the strong hydrogen bond interactions between the [KI3]2− perovskite framework and R-3AQ2+ cations. These results suggest that the mechanical robustness of this multifunctional ( R-3AQ)KI3 makes it a good candidate material for sensing applications.

Chiral hybrid metal halides have been widely studied in the field of photondetectors, chiral optics, and spintronics due to their great structural flexibility and suitable bandgaps. Inspired by such great progress made in the abovementioned fields, continuous efforts need to be paid to seek other interesting applications for chiral hybrid metal halides. Herein, the synthesis of a pair of one‐dimensional enantiomorphic hybrid metal halide piezoelectrics, R/SMPCdCl4(R/SMP = R/S‐2‐methylpiperazine), and their applications in piezoelectric energy harvesting and sensing are reported. Density functional theory calculations show that these chiral piezoeletrics possess low elastic properties and high piezoelectric constants (16.71, 8.39, and 7.35 pC N−1). In addition, devices made of RMPCdCl4/PDMS (PDMS = polydimethylsiloxane) composite films are fabricated for piezoelectric energy harvesting and sensing. The piezoelectric energy harvesters with optimized content of 15 wt% RMPCdCl4/PDMS show not only excellent performance with an open‐circuit voltage of 2.57 V, short‐circuit current of 0.37 μA, and power density of 0.55 μW cm−2 but also outstanding stability of more than 3500 cycles. Meanwhile, these piezoelectric energy harvesters exhibit prominent sensing properties for detecting tapping, finger bending, walking, and running. It is demonstrated that chiral hybrid metal halides hold great potential in intelligent wearable and sensing devices.