Guest‐Induced Activation of Multicolor Photoluminescence in Naphthalene Bisimide Liquid Crystals

Abstract

ABSTRACT Achieving color‐ and lifetime‐tunable emission in processable materials remains challenging, as most of the available advanced materials systems exist only in impractical solutions or hard‐to‐process crystals. Liquid crystals (LCs) represent a promising platform due to their processability, though previous work has mainly controlled emission color by external fluorophore doping. In this work, we present a supramolecular strategy to activate and tune both photoluminescence (PL) color and lifetime in naphthalene bisimide (NBI) LCs by embedding electron‐rich guests. The electron‐deficient NBIs form columnar hexagonal mesophases stabilized by nanosegregation of aromatic cores and aliphatic side chains, providing a suitable environment for charge‐transfer (CT) interactions. Incorporating electron‐rich polycyclic aromatics, carbazole derivatives, or square‐planar Pt(II) complexes yields emissive CT states with tunable emission from visible to near‐infrared (511–685 nm), covering short‐lived fluorescence to long‐lived delayed luminescence of coexisting thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP). Co‐assembling two complementary NBI hosts with one guest enables an energy‐transfer cascade that simultaneously supports green and red dual emission of fluorescence and TADF. This additive‐induced activation and host‐mixing approach greatly broadens the luminescence range accessible in LCs, combining tunable photophysical properties with intrinsic processability for next‐generation optical encoding and security labeling technologies.