Nonbenzenoid polycyclic arenes have attracted great attention because of their unique topological structures and appealing properties; however, they are generally considered as poor luminescent materials due to the ring puckering behavior of the nonhexagons. Acepleiadylene (APD), a nonbenzenoid isomer of pyrene, has been demonstrated as an excellent building block for optoelectronic applications, but its poor photoluminescence quantum yield (PLQY) has hampered its application in luminescent materials. Considering that the ring puckering character can be suppressed by increasing the rigidity of the nonhexagon rings, herein, we propose a novel strategy for enhancing the aromaticity of the nonhexagons to improve the PLQYs of APD derivatives. Electron-withdrawing cyano groups are introduced on the five-membered ring of APD to enhance the charge-separated character and thus the aromaticity of the nonhexagons, endowing the cyano-substituted APDs (CNAPD and 2CNAPD) with better rigidity. Therefore, the cyano substitution successfully suppresses the nonradiative energy dissipation caused by the ring puckering, improving the PLQY from 2.4% for APD to 14% for CNAPD, and to 63% for 2CNAPD. In addition, the enhanced rigidity also suppresses the vibration sideband of the photoluminescence spectra, leading to an ultra-narrowband emission from 2CNAPD with a full-width at half-maximum (FWHM) of 13 nm (47 meV), which is a new record in organic molecules. These results demonstrate that APD derivatives have great potential in highly efficient luminescent materials with high color purity via the aromaticity regulation strategy, which provides a novel concept for designing nonbenzenoid luminescent materials.

非苯环多环芳烃因其独特的拓扑结构和吸引人的性质而受到广泛关注；然而，由于非六边形的环褶皱行为，它们通常被认为是较差的发光材料。苊二烯（APD）是芘的一种非苯环异构体，已被证明是光电应用的优异构建模块，但其较差的光致发光量子产率（PLQY）阻碍了其在发光材料中的应用。考虑到可以通过增加非六边形环的刚性来抑制环褶皱特征，本文提出了一种增强非六边形环的芳香性以提高APD衍生物的PLQY的新策略。在APD的五元环上引入吸电子氰基，增强电荷分离特性，从而增强非六边形的芳香性，赋予氰基取代的APD（CNAPD和2CNAPD）更好的刚性。因此，氰基取代成功地抑制了环褶皱引起的非辐射能量耗散，将PLQY从APD的2.4%提高到CNAPD的14%，以及2CNAPD的63%。此外，增强的刚性还抑制了光致发光光谱的振动边带，导致2CNAPD实现超窄带发射，半峰全宽（FWHM）为13 nm（47 meV），创下新纪录在有机分子中。这些结果表明，APD衍生物通过芳香性调节策略在高色纯度的高效发光材料方面具有巨大的潜力，为设计非苯类发光材料提供了新的概念。