Аннотация:This article is devoted to a detailed study of structural features of spiropyrans of the 1,3-benzoxazine-4-one series with various substituents in the 6′ position of the 2H-chromene moietyusing single crystal X-ray diffraction analysis, as well as IR and NMR spectroscopy, includingvarious two-dimensional NMR techniques. Intermolecular interactions and cavities in crystals ofcompounds were studied using the CrystalExplorer 21.5 software package. Spectral-kineticstudies of the obtained compounds revealed the presence of photochromic properties for nitrosubstitutedspiropyran. The mechanism of isomerization transformations of target compoundswas studied using quantum-chemical calculations based on DFT methods. The calculation resultsmade it possible to determine the most energetically favorable merocyanine conformers ofspiropyrans and helped to explain the observed photochromic activity.