Multimodal Emission Host‐Guest Organic Room‐Temperature Phosphorescent Materials: Full‐Color Tunability, Multi‐Stimuli Responsiveness, and Applications

Abstract Host‐guest doped systems have demonstrated significant application prospects in organic luminescent materials, especially in application areas such as multicolor display technology, information encryption, and bioimaging. However, achieving both multi‐stimuli response and full‐color luminescence within a single host‐guest system remains a significant challenge. Herein, the rational design and successful synthesis of a donor‐acceptor (D‐A) molecule, TOT‐B, are reported. Significantly, when benchmarked against the donor molecule TOT, TOT‐B demonstrates remarkable ratiometric multi‐stimuli responsiveness toward light, fluoride ions, and pH changes in solution. Meanwhile, an isomorphic doping strategy is employed by blending TOT and TOT‐B at different molar ratios, successfully constructing a full‐color tunable photoluminescent crystal (blue to orange‐red). Among them, the T‐Y crystal exhibits rare multimodal emission properties, including mechanochromism (MC), mechanoluminescence (ML), and room‐temperature phosphorescence (RTP). In addition, the combination of the TOT‐B guest with various host molecules, such as cholic acid (CLA), benzophenone (BP), boric acid (BA), and polyethylene terephthalate (PET), can all exhibit phosphorescence, demonstrating excellent host‐guest RTP versatility. This study elucidates correlations between host‐guest interactions and luminescent properties via molecular engineering, enabling full‐color luminescence and multi‐stimuli responsiveness within a single system. These materials show utility in information encryption, dynamic anti‐counterfeiting, and intelligent displays.