The steady-state fluorescence emission spectrum of SCPP[8] was further measured (Figure ). SCPP [8] and [8]CPP showed cyan and yellow fluorescence in tetrahydrofuran (THF) with fluorescence maxima at 475 nm and 533 nm, respectively. The fluorescence quantum yield (ΦF) was determined to be ~3% using anthracene in ethanol as the reference (ΦF = 30%), and the yield is lower than that of [8]CPP (ΦF = 10%), which probably results from its high proportion of nonradiative decay in the low-energy emission region.