A series of mono- to hexabrominated BOPHY dyes have been regioselectively synthesized in 41-96% yields from bromination of parent bis(difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (BOPHY), bromination of hydrazine-linked bispyrrole intermediate, or brominated 2-formylpyrrole precursors in moderate to excellent yields. The reactivities of these polybrominated BOPHY dyes were further studied via regioselective nucleophilic substitution or Suzuki/Stille cross-coupling reactions from which a series of 5- or 5,5'-substituted BOPHYs with amine, pyrrole, thiophene, and phenyl groups were obtained in moderate to high yields of 37-94%. The regioselectivities of both the bromination and nucleophilic substitution reaction, and these resultant BOPHY dyes, are confirmed by NMR, HRMS, and crystal structures. The spectroscopic properties of these resultant BOPHYs were studied, and most of them showed strong absorbance and bright fluorescence with maximum wavelengths centered at between the range of 430 and 660 nm. Their absorption and emission spectra were red-shifted for each bromine atom incorporated. The positions in which bromines or substituents are attached modulate the photophysical properties of the resulting BOPHY dyes.

Multichromophoric boron dipyrromethene (BODIPY) dyes have been efficiently synthesized from a one‐pot condensation of acyl chloride with 2,4‐dimethylpyrrole and have been converted to energy transfer cassettes through a one‐pot Knoevenagel condensation. Various BODIPYs containing 2‐ketopyrrole unit were also isolated as the side products and one of their BF2 complex was also isolated from these condensation reactions. The fluorescence quantum yields of these phenylene bridged dimers and trimer are much lower than those of their corresponding monomers. A significant decrease of the fluorescence quantum yield was observed in most polar solvents for these dimers and trimer, which may be due to a possible symmetry breaking resulted intramolecular charge transfer (ICT) in the excited state. Efficient energy transfer between the donor and acceptor was observed in these energy transfer cassettes, which could be useful as large pseudo‐Stokes shift fluorescent dyes with potential applications in diverse fields.