Isomer Engineering of Phenazine and Tetraphenylethylene Derivatives for Enhanced Fluorescence in both Solid and Aggregation States

Isomer engineering represents a strategy that preserves both the electron donor‐acceptor connectivity and elemental composition of fluorescent molecules, while enables effective modulation of the electronic structure and holds potential for elucidating the influence of molecular architecture on fluorescence behavior. In this work, four new phenazine and tetraphenylethylene (TPE) derivatives were designed and synthesized through an isomer engineering strategy and a Suzuki‐Miyaura coupling reaction. The TPE‐based luminogens were introduced into the phenazine core at the 2,7‐ or 3,6‐positions, resulting in the designation of the four compounds as 27TNE, 36TNE, 27TE, and 36TE, respectively. Among them, 27TNE and 36TNE exhibit characteristic aggregation‐induced emission properties with high fluorescence quantum yields in the solid state (0.49 for 27TNE, 0.35 for 36TNE), whereas 27TE and 36TE show dual‐state emission (DSE) with moderate fluorescence in both solution (0.74 for 27TE, and 0.64 for 36TE in dimethylformamide (DMF)) and solid states. The density functional theory calculations reveal the influence of different isomerization and central cores on the fluorescence behavior of these compounds.