Programming Dual-mode Outputs with Photoreconfigurable Supramolecular Switches

Photoreconfigurable supramolecular switches for programming dual-mode optical outputs are developed in a pyrene-functionalized diacetylene system. The molecular design harnesses the synergy and competition between directional hydrogen bonding and π–π stacking. This not only guides the supramolecular assembly into an ordered state but also enables the pyrene moiety to act as an intrinsic sensitizer, permitting polymerization upon longer-wavelength light irradiation. Such preorganization facilitates the topochemical polymerization of the diacetylene units and concurrently governs the photophysical signature of the pyrene probes. This polymerization triggers a complete fluorescence transition from excimer to monomer emission, arising from a light-induced supramolecular reconfiguration that switches the dominant intermolecular interaction from π–π stacking to hydrogen bonding. The resulting polydiacetylene material exhibits highly reversible thermochromism and mechanochromism. This mechanism allows for the on-demand programming of both color and fluorescence, establishing a versatile platform for multi-level optical encoding and high-security anti-counterfeiting.