Near-Infrared Twisted Polycyclic Arene-Fused BisBODIPYs through a Tandem Inter- and Intramolecular Scholl Reaction

Five novel polyaromatic-ring-fused bisBODIPYs have been synthesized from corresponding readily available α-arylBODIPYs through a FeCl₃-mediated tandem inter- and intramolecular oxidative aromatic coupling reaction. These resultant bisBODIPYs show twisted planar conformations, strong absorptions (ε up to 1.8 × 10⁵ M^-1 cm^-1), and good fluorescence emissions in the near-infrared region (NIR, 660-734 nm) and good intersystem crossing efficiencies (Φ_Δ = 18.9% for dimer 2d in toluene), demonstrating their promising potential applications as heavy-atom-free photosensitizers.