The electronic circular dichroism (ECD) spectra of the resolved isomers of 6-Mes (Figure ) show a mirror-image relationship. A comparison of the experimental data with the TD-DFT simulated spectra allowed for the assignment of the absolute configuration of the first and second fractions as (M)-and (P)-enantiomers, respectively. The calculations reproduce reasonably well the general shape of the ECD spectrum of (M)-6-Mes. Enantiomer (M)-6-Mes exhibits negative Cotton effects (CEs) in the region from 267 to ca. 410 nm ( = -105 m -1 cm -1 at 286 nm,  = -103 m -1 cm -1 at 308 nm,  = -17 m -1 cm -1 at 369 nm) and an intense positive CD band at 245 nm ( = +290 m -1 cm -1 ). The absolute values of the absorption anisotropy factors (gabs) are typical of helicenes and amount to 4.9×10 -3 at 245 nm, 5.1×10 -3 at 286 nm and 5.0×10 -3 at 308 nm. The weak lowest-energy CD band at 369 nm corresponds to |gabs| of 1.8×10 -3 . While the largest ECD of 6-Mes is comparable to that of carbo [6]helicene, the latter compound features somewhat higher maximal |gabs| value (9.2×10 -3 in both