Solid thin films of sugar gels containing ionic dyes, such as flavylium perchlorates and Methylene Blue, revealed reversible color changes toward the changes in temperature and humidity. Absorption spectra of the thin films revealed extended aggregates with only a weak shoulder of the dye monomer even at high temperature, as compared with aqueous hydrogel matrices which showed strong monomer band. The thin films revealed good reversibility toward temperature changes and moderate reversibility toward humidity changes.