Bridged Indolizine‐Naphthyridines: Synthesis and Initial Photophysical Characterization

In this work, we synthesized a new series of hybrid compounds combining an indolizine unit and a 1,8‐naphthyridine moiety through an optimized Friedländer reaction. These systems were designed to evaluate how electronic effects and conformational rigidity influence their photophysical properties. The compounds were obtained in up to 95% yield and in short reaction time. Among the synthesized derivatives, compounds 3a and 3j were selected for an initial photophysical analysis. Both exhibited solvent‐dependent absorption and emission behavior, with 3a showing the highest emission quantum yield. The formation of a six‐membered ring connecting both heterocycles increases molecular rigidity, restricts bond rotation, and facilitates intramolecular charge transfer. The promising initial results pave the way for future investigations into the potential applications of these novel indolizine‐[1,8]‐naphthyridine hybrids in fluorescence‐based materials.