1,7-Dihalogenated BODIPYs: Synthesis, Structure and Photophysics

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) and its derivatives are highly useful fluorescent dyes employed in myriad applications in chemistry and biology. Here, we revisit a series of dihalogenated (Cl, Br, I) BODIPY derivatives with rare 1,7-regiochemistry. In addition to their synthesis and structural characterization, we fill in a missing piece of the current literature by delineating their photophysical behavior, including the light-driven generation of singlet oxygen (1O2) which is mediated with particularly high efficiency by the heavier diiodinated congener.