ABSTRACT Indolocarbazole (ICz)‐based multi‐resonance (MR) emitters have garnered significant attention due to their narrowband emission and synthetic accessibility. However, the structural diversity and accessible spectral range of such systems remain notably constrained, particularly in the yellow region. Notably, introducing a yellow component alongside the conventional red, green, and blue primaries can significantly widen the display color gamut, potentially surpassing the stringent BT.2020 standard. This addition is also key to enabling faithful reproduction of warm, natural hues such as skin tones and sunlight and to reducing the overall power consumption of OLED displays. Herein, we report a one‐pot synthetic strategy to directly construct an asymmetric framework, ICz‐IAD, which integrates fused five‐ and six‐membered aza‐heterocycles. This tailored molecular structure effectively extends π‐conjugation while preserving high rigidity, thereby overcoming the typical trade‐off between emission redshift and spectral narrowness. The resulting ICz‐IAD emitters represent the first family of yellow‐emitting MR materials based on an ICz scaffold, exhibiting photoluminescence peaks at 538–543 nm with full width at half maxima of approximately 24 nm. Remarkably, the corresponding OLED devices achieve record‐high performance among fluorescent yellow emitters, delivering a power efficiency of 105.3 lm W −1 and a current efficiency of 94.4 cd A −1 while maintaining excellent color purity.
Wu et al. (Tue,) studied this question.