Replacing phenyl ring with thiophene: an approach to longer wavelength aza-dipyrromethene boron difluoride (Aza-BODIPY) dyes.

In the orignial 1,3,5,7-tetraphenyl aza-BODIPY, replacing the phenyl rings with thiophene achieved significant bathochromic shifts. One of the target molecules, DPDTAB, emitting strong NIR fluorescence with a quantum yield of 0.46 in acetonitrile, is a very competitive NIR fluorophore.