Bright and Color‐Tunable Circularly Polarized Excimer Emission from Pre‐Organized, Naphthalene Diimide Molecular Designs

Within the realm of organic materials, excimer emission has emerged as an efficient strategy for developing circularly polarized luminescence (CPL)-active systems, owing to its intrinsic combination of high brightness and large dissymmetry factors (g_lum). Nevertheless, progress with this approach has been constrained by limited color tunability and substrate scope, with red-emissive circularly polarized excimer emission remaining essentially unexplored. Herein, we demonstrate that core-substitution chemistry of naphthalenediimide (NDI) derivatives offers a versatile platform to achieve tunable excimeric CPL spanning the visible range, from 500 nm (green) to 650 nm (red), reported here for the first time. By employing cyclophane and clip-like pre-organized molecular architectures, excited-state chirality was effectively introduced, affording bright circularly polarized excimer emission with impressively high g_lum values of up to 4.0 × 10^-2 (green) and 1.5 × 10^-2 (red), along with remarkable CPL brightness. These results, combining outstanding brightness with the rare realization of red-emissive excimeric CPL, place these systems among the highest-performing small molecule CPL emitters to date.