Synthesis and optical properties of a new class of pyrromethene–BF2 complexes fused with rigid bicyclo rings and benzo derivatives

A new class of boron dipyrromethene (BDP) dyes fused with rigid bicyclo[2.2.2]octadiene units are prepared, which are converted into benzo BDP dyes via a retro Diels–Alder reaction; the absorption and fluorescence spectra of the new dyes are discussed.