“…58 Much work has been published on the basis of this concept over the past years (e.g. benzo-fused BODIPY (112 -164), [59][60][61][62][63][64] benzo-fused B,O-chelated BODIPY (165 -167), 65,66 benzo-fused aza-BODIPY (168 -177), 37,67,68 and areno-fused BODIPY (178 -186) 69,70 ), and the following briefly describes the tendency of the effect of modifying the optical properties: about a 50 nm red shift is achieved by introducing one benzene ring, resulting in similar, or a bit lower, optical properties compared to that of the original BODIPY (spectral sharpness, extinction coefficients, quantum yields). The extinction coefficients are for the most part almost identical to, or lower than, those of BODIPY (~80000 M -1 cm -1…”