The sol-gel technique allows preparation of pure inorganic glasses or composite glasses of inorganic and organic nature at low temperature. Incorporation of organic molecules with desired spectral characteristics is the subject of our research. Specific cases include preparation of stable tunable lasers in the visible based on photostable dyes; glasses doped with dyes characterized by double-proton transfer with good separation between absorption and emission; new materials having nonlinear properties; and glasses with dyes sensitive to ambient acidity and basicity. Four types of these glasses are discussed.