From nature-inspired electron acceptors to BioAIE materials with polarity- and polymorphism-dependence for anti-counterfeiting

Organic optical functional materials show immense potential in smart materials, bioimaging, and theranostics. Despite their widespread utility, most photofunctional materials are principally derived from petrochemical sources, facing limitations in sustainability and monotonous skeletal structure. Nature-derived compounds offer unique molecular scaffolds that can inspire the design of innovative optical functional materials in addition to renewability and sustainability. Herein, we report the rational design of a novel biomass-based electron acceptor, dehydroabietic acid quinoxaline (DAQx), derived from renewable rosin. By coupling DAQx with triphenylamine, we constructed a series of electron donor-acceptor-type natural product-based aggregation-induced emission materials with tunable conjugation and charge transfer characteristics. These compounds exhibit dual-state responsive fluorescence, demonstrating both solvent-dependent emission in solution and polymorphism-dependent luminescence in solids. Remarkably, DAQx-BP displays distinct green and yellow fluorescence in different crystalline polymorphs, despite near-identical molecular packing with intermolecular interaction differences of <0.01 Å, which is a rare phenomenon highlighting extreme structure-property sensitivity. Leveraging these unique photophysical properties, DAQx-BP is applied in dual-modal smart anti-counterfeiting in both solution and aggregate states. This work not only provides a general strategy for designing sustainable, natural product-derived electron acceptors but also significantly expands the functional applications of natural resources in advanced optical materials.