Dynamic Time‐Dependent Emission in Solution and Stable Dual Emission in Solid Matrix Exhibited by a Single‐Component Fluorescence System

Organic luminescent materials with time‐dependent emission colors show promising applications in the fields of chemical sensing, high‐resolution bioimaging, and high‐security information encryption. Herein a time‐dependent fluorescence system based on a spirocyclic scaffold‐bridged cyanostilbene dimer (SDCS) as the single component in a mixed CH3CN/H2O solvent is presented. Specifically, the original orange‐emitting nanoparticles prepared from SDCS by reprecipitation can transform into green‐emitting nanosheets over time driven by supramolecular self‐assembly. It is worth noting that such a transformation rate can be controlled by tuning the water fraction. Based on these unique properties, fluorescent binary codes are developed, enabling time‐dependent information encryption with a higher level of security. Moreover, the dual color can be individually fixed by solid matrices such as hydrogel or powder. The obtained luminescent powders are successfully used in two‐color fluorescence imaging of latent fingerprints. This work demonstrates the use of a supramolecular strategy to control multiple emissions in a single‐component system for multifunctional applications. A spirocyclic‐scaffold‐bridged cyanostilbene dimer (SDCS) is designed and synthesized, which exhibits multiple fluorescence properties: excited‐state intramolecular proton‐transfer (ESIPT), aggregation‐induced emission enhancement (AIEE), and time‐dependent self‐assembly induced emission (TD/SAIE). Based on the ESIPT‐AIEE‐TD/SAIE triple fluorescence mechanism, SDCS can be used for time‐dependent information encryption and two‐color fluorescence imaging of latent fingerprints.