Later Krongauz described unusual phase transitions of molecules composed of mesogenic and spiropyran moieties, which he named "quasi-liquid crystals." A micrograph of their mesophase appeared on the cover of Nature in a 1984 paper, “Quasi-Liquid Crystals.” The investigation of spiropyran-merocyanine self-organized systems, including macromolecules (see, for example, Fig. 2), has continued over the years.