SolventMediated Hydrogen Bond‐Driven Self‐Assembly Materials for Tunable Phosphorescence

Abstract Organic room‐temperature phosphorescence (RTP) materials with tunable emission intensity, lifetime, and quantum yield are vital for optoelectronics, bioimaging, and anti‐counterfeiting. Herein, a solvent‐mediated hydrogen bond‐driven self‐assembly strategy is reported to regulate the RTP performance of assemblies derived from melamine (MA), cyanuric acid (CA), and 3,5‐dicarboxyphenylboronic acid (IB). Protic (H 2 O) and aprotic (dimethyl sulfoxide, DMSO) solvents modulated the assembly process, leading to a gradual transformation from defect‐rich nanocrystalline assemblies with weak RTP to highly ordered crystalline assemblies with enhanced phosphorescence. Increasing water content (from 0% to 100%) of the mixed solvent of H 2 O and DMSO could continuously improve the crystallinity and RTP performance of the material, with phosphorescence lifetime extending from 0.81 to 1.18 s and phosphorescence quantum yield rising from 1.73% to 11.93%. Notably, reversible modulation of RTP emission could be achieved through vapor stimuli, where alternating exposure to H 2 O and DMSO vapors induced repeatable enhancement and attenuation of phosphorescence. The universality of this strategy is further demonstrated using additional phosphor guests. These findings highlighted the potential of solvent‐mediated hydrogen‐bonded assemblies as adaptable platforms for stimulus‐responsive RTP materials.