Second, ECD spectroscopy allowed to directly probe helicity of the scrutinized isomer, which is opposite for CT-1 and BR-1. The experimentally observed ECD spectra clearly show that helicity of the scrutinized isomer is the same as for CR-1, which is manifest in the overall very similar ECD spectrum and Cotton-effect features (Figure ). Further, the corresponding calculated ECD spectra are in very close agreement with the experimental ones for both, CT-1 and CR-1. They are exact enough to distinguish these two isomers, which are only differing in their axial chirality of the biaryl moiety as manifested in the Cotton-effect features between 250 nm and 300 nm (Figure ). The inverted helicity of isomer BR-1 expectedly leads to opposite Cotton-effects especially in the visible region of the calculated ECD spectrum, which does not match at all with the experimentally observed spectrum of the isomer enriched in apolar solvents (Figure ). Thus, this isomer could unambiguously be assigned to the CT-1 isomer by the comprehensive spectroscopy analysis.