Cheng Qu, Yize Wu, Lian Duan, Yuewei Zhang
ABSTRACT Developing efficient and stable blue organic light‐emitting diodes (OLEDs) remains challenging due to the inherent trade‐off between efficiency and operational lifetime. While multiple resonance thermally activated delayed fluorescence emitters offer narrowband emission with reduced excited‐state energy, their planar structure, long‐lived excitons, and deep highest occupied molecular orbital levels cause detrimental aggregation and instability. Here, we introduce a “3D anchoring” strategy that strategically enhances intramolecular noncovalent interactions. A sterically encumbered, sandwich‐like architecture with carbazole‐based dual anchors simultaneously suppresses π–π stacking and reinforces bond dissociation energy, boosting intrinsic stability. The proof‐of‐concept emitters demonstrate bright blue photoluminescence in solution, with photoluminescence quantum yields surpassing 92% and exceptionally narrow emission bands down to 18 nm. The corresponding optimized OLED device achieves a maximum external quantum efficiency of 38.2%, alongside record‐high current and power efficiencies (59.2 cd A − 1 and 66.8 lm W − 1 , respectively), excellent color purity (CIEy < 0.25), and a 2.3‐fold improvement in operational lifetime. This work thereby presents a widely applicable design principle for next‐generation high‐performance blue emitters.