• A layered hybrid crystal integrates fluorescence, mechanical flexibility, conductivity, and cryogenic durability via reduced graphene oxide and thermally responsive polyurethane encapsulation.
• The hybrid crystal enables real-time dual-mode sensing of humidity (1.65% RH−1) and temperature (0.46% °C−1) with high sensitivity and cycling stability.
• Infrared-induced photothermal actuation at −150 °C allows reversible crawling and walking under cryogenic conditions.
• This work establishes hybrid crystalline materials as versatile and scalable platforms for next-generation multifunctional devices in biomedical, flexible electronics, and energy applications.