Synthesis and Solvatochromic Photophysics of Novel Benzanthrone‐Based Schiff Base and Amine Derivatives for Next‐Generation Optoelectronic and Photovoltaic Applications

The rational design of organic chromophores with tunable photophysical and charge transfer properties is a key strategy for advancing next‐generation optoelectronic and photovoltaic (PV) applications. In this work, we report the synthesis and detailed characterization of two novel benzanthrone derivatives: the Schiff base 2‐bromo‐3‐[N‐(4‐methoxybenzylidene)amino]benzo[de]anthracen‐7‐one (EK1) and its reduced secondary amine analog 2‐bromo‐3‐[N‐(4‐methoxybenzyl)amino]benzo[de]anthracen‐7‐one (EK2). Structural confirmation was achieved using FTIR, MS, HRMS, NMR, and UV–vis spectroscopy. Their photophysical, solvatochromic, and excited‐state behaviors were systematically evaluated in eight solvents spanning a wide polarity range. EK1 exhibited higher molar absorptivity, wider bandgap, and significantly larger Stokes shifts, reflecting strong intramolecular charge transfer (ICT) enabled by its rigid, conjugated C=N linkage. In contrast, EK2 displayed redshifted absorption and emission maxima due to enhanced donor–acceptor interactions and a narrower HOMO–LUMO gap, while producing narrower emission profiles and reduced Stokes shifts associated with its more flexible–NH–functionality. These contrasting trends reveal clear structure–property relationships that demonstrate how imine‐to‐amine conversion regulates ICT strength, excited‐state stabilization, and solvent‐dependent fluorescence response. The pronounced solvatochromism, tunable visible‐range emission, and strong environment sensitivity exhibited by both derivatives underscore their promise as versatile fluorophores for applications in chemical sensing, spectral conversion layers, fluorescence imaging, and energy‐efficient optoelectronic devices.