Multicomponent C−H Activation/Annulation Polymerizations Toward Structurally Regular Polyelectrolytes With Light‐Boosted Antibacterial Potency

ABSTRACT C−H activation/annulation polymerization (CAAP) has emerged as a powerful synthetic tool toward heteroaromatic polyelectrolytes, but its broader application is severely limited by the regioisomerization issues arising from the use of asymmetric diyne monomers. Access to structurally regular heteroaromatic polyelectrolytes via CAAP reactions is highly desirable yet remains challenging. In this study, we develop a one‐pot multicomponent CAAP strategy that intrinsically circumvents regioisomerization by employing symmetric and monofunctional internal alkynes as comonomers to polymerize with aromatic dialdehydes and diamines. A series of structurally well‐defined polyelectrolytes featuring multiaryl‐substituted dibenzo[ a , f ]quinolizium units were in situ generated with high molecular weights (absolute M w up to 224700 g/mol) in good yields (up to 91.2%). The resulting polyelectrolytes exhibited excellent solubility and readily tunable photophysical properties, with fluorescence emission extending to the first near‐infrared region. Moreover, these structurally regular conjugated polyelectrolytes exhibit synergistic photothermal and photodynamic effects, achieving potent light‐enhanced antibacterial and antibiofilm activities against both Gram‐positive and Gram‐negative bacteria, including drug‐resistant strains. This work provides a versatile polymerization platform for the precise synthesis of diverse functional polyelectrolytes with promising applications in optoelectronics and antimicrobial therapeutics.