Synthesis of Highly Luminescent Chiral Nanographene

Chiral nanographenes with both high fluorescence quantum yields (ΦF) and large dissymmetry factors (glum) are essential to the development of circularly polarized luminescence (CPL) materials. However, most studies have been focused on the improvement of glum, whereas how to design highly emissive chiral nanographenes is still unclear. In this work, we propose a new design strategy to achieve chiral nanographenes with high ΦF by helical π‐extension of strongly luminescent chromophores while maintaining the frontier molecular orbital (FMO) distribution pattern. Chiral nanographene with perylene as the core and two dibenzo[6]helicene fragments as the wings has been synthesized, which exhibits a record high ΦF of 93 % among the reported chiral nanographenes and excellent CPL brightness (BCPL) of 32 M−1 cm−1. A perylene‐based chiral nanographene has been synthesized through helical π‐extension of highly emissive chromophores whilst maintaining the frontier molecular orbital distributions. This nanographene exhibits excellent luminescence properties, with a record high ΦF of 93 % among chiral nanographenes and a remarkable CPL brightness of 32 M−1 cm−1.