Аннотация:In this paper, we report the conditions and results of the synthesis of solid solutions and flux growthof single crystals with the general formula La1 − x – yTbxEuyMgB5O10 from a K2Mo3O10-based high-temperature solution. The structural properties, composition, thermal characteristics, Tb3+ and Eu3+ luminescence spectra, and excitation spectra of the solid solutions have been studied in the ranges 0.2 < x < 0.7 and 0.1 < y < 0.6. We have calculated CIE luminescence spectra of the single crystals and fabricated operating prototype emitters using them.