Post‐Synthetic Functionalisation of Benzo[ a ]ullazines for Improving UV–Vis Absorption Profiles

π‐Extended derivatives of ullazine (IUPAC name: indolizino[6,5,4,3‐ ija ]quinoline) are unique nitrogen‐doped polycyclic aromatic compounds with potential optoelectronic applications. Among these, benzo[ a ]ullazines are promising but less accessible. Herein, we report post‐synthetic functionalisation of simple benzo[ a ]ullazines for systematic synthesis of new compounds with improved visible light absorption properties.