meso-Substitution controlled synthesis of BODIPY-DPM conjugates: a pathway to tailored photophysical properties

meso-Substituent-controlled reactivity in meso-aryl-1,3,5,7-tetramethyl BODIPY facilitates selective mono- or bis-condensation with pyrrole-2-aldehyde or 1,9-diformyl-dipyrromethanes. The resulting π-extended BODIPY-DPM/pyrrole conjugates exhibit deep-red absorption, NIR emission, efficient triplet formation, and high singlet-oxygen production, enabling heavy-atom-free photodynamic activity (IC₅₀ = 0.95 µM) with negligible dark toxicity.