Small Organic Molecule-Based Multicolor Fluorescent Smart Materials: From Design Principles and Optical Properties to Versatile Applications.

As an emerging frontier in functional material science, multicolor fluorescent smart materials have garnered significant interest because of their inherent versatility and precisely tunable fluorescent characteristics, enabling the development of increasingly sophisticated and functional platforms. In this Outlook, we summarize the recent advances in small-organic-molecule-based multicolor fluorescent materials, covering their design principles, optical properties, and versatile applications. The various strategies for achieving multicolor fluorescence emission could range from classic approaches based on modulation of electronic excited states and molecular intrinsic structure to newly emerging methods, such as molecular conformation switching and regulation of molecular aggregation/packing. We also present the advanced applications of the multicolor fluorescent materials driven by these design strategies, including fluorescence sensing, anticounterfeiting, information encryption, and decryption. Finally, an outlook on the main challenges and future opportunities for multicolor fluorescent materials is previewed, aiming to accelerate the advancement of smart materials and devices. We hope that these insights will inspire further innovative research on multicolor fluorescent smart materials and their advanced applications.