Harnessing Photons for Trifold Output: Chromic, Luminescent, and Mechanical Transformations in a Smart Material

ABSTRACT By leveraging the dual photochemical activity of vinylpyridinium building blocks, the concurrent [2+2] photocycloaddition and photoinduced electron transfer are integrated within coordination polymer frameworks to achieve triple photoresponses, simultaneously generating photochromism, fluorescence modulation, and photomechanical actuation within a single crystalline system. The efficient photocycloaddition occurs in the interpenetrated framework despite the criss‐crossed olefin arrangement, resulting in rapid stress accumulation and release that manifests as explosive photosalient behavior alongside optical switching. The framework‐dependent ligand conformations produce distinct fluorescence readouts, allowing the progress of the cycloaddition to be monitored optically. When embedded in poly(vinyl alcohol) matrices, the crystal‐level micro‐strain is amplified into programmable macroscopic motions including straightening, crawling, and gathering under single‐wavelength irradiation. This work provides a design strategy for integrating multiple photoresponses into a single material, contributing to programmable light‐driven actuators and adaptive devices.