Time‐Evolving Aqueous Organic Room‐Temperature Phosphorescence from a Native Cyclodextrin‐Based Supramolecular Co‐Assembly

Abstract Aqueous organic room‐temperature phosphorescence (AO‐RTP) is a topic of intense interest for materials and biological photonics. Herein, an efficient supramolecular time‐evolving AO‐RTP is developed through dynamic directional self‐assembly between native α‐cyclodextrin (α‐CD) and 4′‐bromo‐4‐biphenylboronic acid (BBA) using a synergistically hierarchical confinement strategy. The initially fluorescent BBA undergoes multilevel rigidification in water through covalent cross‐linking and cooperative noncovalent interactions with α‐CD. This process significantly suppresses non‐radiative transitions and circumvents quenchers, thus resulting in time‐evolving phosphorescence enhancement. Over 40 h, the nascent phosphorescence signal intensifies gradually, culminating in an excellent phosphorescence quantum yield of 63.48% and lifetime of 16.75 ms. In light of its aqueous processability with satisfactory phosphorescence performance, this metal‐free system serves as a green phosphorescent reagent for cell imaging, anti‐counterfeiting, and high‐contrast fingerprint visualization. This work provides a general paradigm for eco‐friendly macrocyclic AO‐RTP materials via hierarchical supramolecular‐covalent rigidification.