One‐Shot Synthesis of B/N‐Doped Calix[4]arene Exhibiting Narrowband Multiple Resonance Fluorescence

Abstract A novel macrocycle of B/N‐doped calix[4]arene (C‐BN) was synthesized by a one‐shot double boronation. Owing to the structural tension and electron‐donating properties of the nitrogen atoms in the macrocycle, reaction selectively proceeds between the adjacent benzene rings outside the macrocycle. C‐BN shows a highly centrosymmetric structure with two multiple resonance (MR) fragments bridged by tertiary amine groups at the 1,3 positions of the benzene ring. Benefiting from the large intermolecular distance (>4.6 Å) between adjacent MR‐emitting cores, C‐BN also exhibits excellent narrowband emitting features against aggregation‐induced quenching and spectrum broadening. Optimized organic light‐emitting diode devices based on C‐BN exhibit high maximum external quantum efficiencies of 24.7–26.6 % and small full width at half maximums of 25–28 nm over a wide doping range of 1–12 wt %.