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Heteroatom‐doped peri‐acenes (PAs) have recently attracted considerable attention considering their fascinating physical properties and chemical stability. However, the precise sole addition of boron atoms along the zigzag edges of PAs remains challenging, primarily due to the limited synthetic approach. Herein, we present a novel one‐pot modular synthetic strategy toward unprecedented boron‐doped PAs (B‐PAs), including B‐[4,2]PA (1 a‐2), B‐[4,3]PA (1 b‐2) and B‐[7,2]PA (1 c‐3) derivatives, through efficient intramolecular electrophilic borylation. Their chemical structures are unequivocally confirmed with a combination of mass spectrometry, NMR, and single‐crystal X‐ray diffraction analysis. Notably, 1 b‐2 exhibits an almost planar geometry, whereas 1 a‐2 displays a distinctive bowl‐like distortion. Furthermore, the optoelectronic properties of this series of B‐PAs are thoroughly investigated by UV/Vis absorption and fluorescence spectroscopy combined with DFT calculation. Compared with their parent all‐carbon analogs, the obtained B‐PAs exhibit high stability, wide energy gaps, and high photoluminescence quantum yields of up to 84 %. This study reveals the exceptional ability of boron doping to finely tune the physicochemical properties of PAs, showcasing their potential applications in optoelectronics. [ABSTRACT FROM AUTHOR]

A novel synthetic strategy was developed for the construction of difficult‐to‐access structurally constrained boron‐doped polycyclic aromatic hydrocarbons (sc‐B‐PAHs) via a cascade reaction from the readily available ortho‐aryl‐substituted diarylalkynes. This domino process involves borylative cyclization, 1,4‐boron migration and successive two‐fold electrophilic borylation. Two types of sc‐B‐PAHs bearing B‐doped [4]helicene (1 a‐1 i) or BN‐doped [4]helicene (1 n‐1 t) and double [4]helicene (1 u‐1 v) are constructed by this cascade reaction. Remarkably, this synthetic strategy is characterized by modest yields (20–50 %) and broad substrate scope (18 examples) with versatile functional group tolerance. The resultant sc‐B‐PAHs show good stability under ambient conditions and are thoroughly investigated by X‐ray crystallography, UV/Vis absorption and fluorescence spectroscopy, and cyclic voltammetry. Interestingly enough, BN‐doped [4]helicene 1 o forms a unique alternating π‐stacked dimer of enantiomers within a helical columnar superstructure, while BN‐doped double [4]helicene 1 u establishes an unprecedented π‐stacked trimeric sandwich structure with a rare 2D lamellar π‐stacking. The synthetic approach reported herein represents a powerful tool for the rapid generation of novel sc‐B‐PAHs, which are highly attractive for the elucidation of the structure‐property relationship and for potential optoelectronic applications. [ABSTRACT FROM AUTHOR]