Аннотация:For the first time, the photo- and thermochemical properties of cymantrenylalkylthiols 1 and 2 werestudied. It was found that thiol 1 is an unstable compound and enters into a spontaneous dimerisation reaction. Photolysis of new compound 5 in DMF resulted in the replacement of the CO ligand with one solvent molecule. The photolysis of thiol 2 led to the formation of intramolecular complexes 7 and R2. The parameters of the IR,NMR and UV-visible spectra changed after irradiation of 2. In the presence of CO, these chelates were converted to the starting tricarbonyl compounds, thereby forming an intermolecular photochromic syste