Reversible phase-transformation-induced thermal quenching in Mn(II) chlorides for high-precision information encryption and thermal energy storage

, respectively. Using two closely spaced PL quenching temperatures, we demonstrate a temperature-window encryption scheme for optical information encryption and anti-counterfeiting, where correct information is revealed only within 333 ≤ T < 343 K. Furthermore, combining latent-heat storage with a temperature-gated PL ON/OFF readout provides a straightforward route to visualized thermal energy storage. This work reveals phase-transition-induced PL quenching and its applications in optical information encryption and visualized thermal energy storage, providing a strategy for designing multifunctional thermo-responsive luminescent materials.