The photophysical properties of helicenes 1-Mes, 6-Mes and 7-Mes were investigated by UV-vis absorption and fluorescence spectroscopy. As shown in Figure and Table , compound 1-Mes and 6-Mes displayed quite strong shoulder absorption bands centred at around 390 nm (387 nm for 1-Mes and 397 nm for 6-Mes), which is in stark contrast to the pristine carbohelicenes that exhibit very weak absorption bands at the longest wavelength (e.g. the molar extinction coefficient ε of [5]helicene C at 393 nm is 200 M -1 cm -1 and the ε of [6]helicene D at ca. 415 nm is ca. 300 M -1 cm -1 ). Similarly, compound 7-Mes also exhibited strong absorptions for the lowest energy transition centered at 374 nm.