Wide‐Range Color‐Tunable Narrowband Fluorescence Emitters Based on 1,2‐BN‐Embedded Polycyclic Aromatic Hydrocarbons

) of 35.5% and 44.3%-the first fluorescent OLEDs to surpass the 40% EQE threshold. Importantly, 1,2-BN-embedded PAHs rival state-of-the-art 1,4-BN-based multiple-resonance (MR) emitters, while offering a substantially simpler, more general synthetic blueprint readily extendable to diverse PAH architectures.