Light‐Controlled Supramolecular Reconfiguration Enables Sustainable Crop Protection

ABSTRACT

Bacterial biofilms fuel antimicrobial resistance, a pressure amplified by repeated deployment of structurally uniform bactericides. Photoswitchable azobenzenes offer light‐driven structural diversity that may temper resistance evolution, but their small‐molecule form limits foliar adhesion. Although supramolecular materials show promise as biofilm inhibitors, photoresponsive supramolecular polymers for this purpose remain largely unexplored. This study reports Azo@CB[8], a multifunctional supramolecular polymer that self‐assembles in water from a de novo azobenzene (Azo) and cucurbit[8]uril (CB[8]). CB[8]‐mediated association preserves photoisomerization, improves cycling stability, and integrates membrane disruption, redox imbalance, biofilm inhibition, sessile‐cell killing, and enhanced foliar affinity. In pot assays, Azo@CB[8] outperforms free Azo and thiodiazole copper against rice bacterial leaf blight, without detectable biosafety penalties, and likewise exceeds both controls against kiwifruit bacterial canker. Notably, photoisomerization perturbs azobenzene‐mediated host–guest interactions while largely retaining bipyridinium‐CB[8] association, thereby reducing supramolecular connectivity and driving reconfiguration of the extended architecture into a smaller, less‐connected supramolecular ensemble. The photoirradiated supramolecular state retains antibacterial efficacy comparable to that of the initial assembly. Together, these findings outline a supramolecular polymer‐based, photoregulated route to greener management of bacterial plant diseases.