Combinatorial chemistry was applied to the optimization of red phosphors used for plasma display panels. Quaternary and ternary combinatorial libraries were developed for (Y,Gd,Lu,Sc)BO3 and (Y,Gd)(BO3 . PO4) systems. Our combinatorial chemistry system consists of solution-based combinatorial synthesis and characterization, enabling the swift scanning of luminance and of Commission Internationale de l'Eclairage (CIE) chromaticity under vacuum ultraviolet light excitation. As a consequence of the combinatorial approach, several new candidates were found to show higher luminance than the commercially available red phosphor for plasma display panels.