Synthesis and Properties of BF₂‑3,3′-Dimethyldiarylazadipyrromethene Near-Infrared Fluorophores

The first synthesis of both organic and aqueous soluble BF₂ chelated 3,3′-dimethyl-5,5′-diarylazadipyrromethenes has been achieved. The fluorophores are emissive in organic and aqueous solvents with high quantum yields in the key biological near-infrared (NIR) spectral region of 675–700 nm. Following efficient cellular uptake from aqueous media the fluorophore can be readily visualized with confocal microscopy.