Boron Hybridization Engineering for Regulating Room Temperature Phosphorescence

Abstract Organic room temperature phosphorescence (RTP) materials have attracted widespread attention for their potential in both fundamental research and advanced technologies. However, their development is hindered by weak spin‐orbit coupling and nonradiative decay. Here, we present a boron hybridization engineering strategy in which arylboronic esters are incorporated into poly(4‐vinylpyridine). By regulating the hybridization state of boron atoms from sp 2 to sp 3 , the phosphorescence properties can be effectively tuned. Simultaneously, the formation of B‐N bonds suppresses nonradiative decay, leading to long‐lived RTP with lifetimes up to 2.23 s. Both experimental evidence and theoretical calculations confirm the occurrence of boron hybridization switching and its decisive role in modulating phosphorescence. Moreover, the B‐N bonds exhibit acid‐base responsiveness, endowing the system with dynamic phosphorescence behavior. Beyond demonstrating triplet exciton control, this work establishes a molecular design principle that may guide the creation of multifunctional organic phosphorescent materials.