Unveiling Symmetry Breaking Charge Separation Dynamics in Near-Infrared Active 3-Pyrrolyl BODIPY Dimers: A Pathway to Efficient Charge Transfer

Symmetry breaking charge separation (SBCS) a fundamental process in natural photosynthesis, remains rare in synthetic neutral systems. Here, we report the first example of ground state SBCS in near-infrared (NIR) active 3-pyrrolyl BODIPY dimers, effectively mimicking the efficient low energy charge transfer seen in biological light harvesting complexes. Unlike the monomer, the dimers exhibit distinct SBCS features, including broad charge-transfer bands (~890–905 nm) in DMSO, dual reversible reductions and complete fluorescence quenching in polar solvents. Single-crystal X-ray analysis reveals a Z-shaped helical conformation stabilized by multidirectional non-covalent interactions and π–π stacking with extended conjugation across six planarized pyrrole units. This packing promotes J type aggregation and strong NIR absorption (λabs = 760–772 nm). Ultrafast transient absorption and decay kinetics in picoseconds timescale correlates with the multicomponent excited state behavior confirming formation of charge separated state in DMSO. DFT and TD-DFT calculations showed a significant reduction in HOMO–LUMO gap as compared to monomer with enhanced delocalization, consistent with the observed NIR activity, charge transfer behavior and solvent responsive excited state dynamics. These results demonstrate a rare synthetic model that captures the essence of nature’s charge separation strategy, offering a blueprint for designing next-generation optoelectronic, photonic and energy harvesting materials.