<i>N</i> -Annulated Indenofluorene: An Isomeric Motif for <i>N</i> -Annulated Perylene

<i>N</i>-Annulated indenofluorene (<b>NIF</b>), a structural isomer of the well-known <i>N</i>-annulated perylene (<b>NP</b>), has been synthesized. While the band gap of <b>NP</b> is larger than that of perylene, the band gap of <b>NIF</b> (1.40 eV) is smaller than that of parent indeno[2,1-<i>c</i>]fluorene (1.60 eV) due to the inclusion of a nearly planar 8π azepine ring in the π-conjugated backbone, enhancing the core antiaromaticity. The ground state properties are evaluated by structural (single-crystal) and spectral (NMR, UV-vis-NIR, and CV) analyses and supported by computations (NICS and ring current). <b>NIF</b> is an ambipolar material with good electron mobility (1.58 × 10^-3 cm² V^-1 s^-1) and high hole mobility (1.79 × 10^-2 cm² V^-1 s^-1), surpassing the hole mobility of the unipolar <b>NP</b> isomer.