Stoichiometry‐driven supramolecular assembly for stable and controlled antifungal delivery

Abstract The conventional agrochemicals suffer from intrinsic drawbacks including high volatility, rapid photodegradation, and poor interfacial retention, which severely compromise their efficacy and raise environmental risks. Herein, we report a stoichiometry‐driven, one‐pot supramolecular assembly strategy to construct pyrimethanil (PYR)‐based nano‐cocrystals and nano‐salts. These systems effectively mitigate the physicochemical deficiencies of PYR, reducing volatilization by 81.15% and 91.42%, respectively, while exhibiting low hygroscopicity and robust phase stability. Crucially, their photolysis resistance increases by 2.36‐fold in solution and 1.55‐fold in the solid state. The nanoformulations also demonstrate superior interfacial affinity, target retention, and form‐dependent tunable release kinetics. Biological evaluations confirm enhanced antifungal activity against Botrytis cinerea , along with high biosafety and plant compatibility. This work highlights the potential of stoichiometry‐driven supramolecular assembly for multidimensional performance tuning, offering a promising path toward next‐generation precision agriculture.