The respective compounds were dissolved in ethanol, toluene or THF [for 16] and their absorbance in the UV-Vis spectrum was adjusted to ca. 0.10-0.20 at the wavelength of excitation. Direct detection of the luminescence emission of 1 O2 at 1275 nm was achieved upon excitation at 500 or 508 nm. Singlet oxygen quantum yields (ΦΔ) were calculated by equation 1, with erythrocin B (ΦΔ = 0.69 in ethanol), or 5,10,15,20-tetraphenylporphyrin (H2TPP) (ΦΔ = 0.68 in toluene) as reference compounds. The wavelength range of the emission was recorded from 1150 nm to 1350 nm; 10 or 15 s integration time; 14 nm excitation slit; 40 nm emission slit. D was calculated from the area under the curve between 1220-1340 nm. Note, that for singlet oxygen quantum yield calculations, the reference and unknown compound should be diluted and measured in the same solvent.