The present invention relates to the field of color filters and LCDs. More specifically, the invention relates to a colorant composition for making color filters comprising pyrimido[5,4-g]pteridine derivatives of formula (I) wherein A1, A2, A3, and A4 are each independently of the others —NR1R2, wherein R1 and R2 are each independently of the others hydrogen, CrC8alkyl, —CO—C1-C8alkyl, —CO—Ce—Cuaryl, —COO—C1-C8alkyl, —COO—Ce—CMaryl, —CONH-d-Cβalkyl or —CONH—Ce-CMaryl, Or A1, A2, A3, and A4 are each independently of the others —OH, —SH, hydrogen, CrC8alkyl, CrC8alkoxy, or C6-C14aryl or —O—C6-C14aryl each unsubstituted or mono- or poly-substituted by halogen, nitro, cyano, —OR10, —SR10, —NR10R11, —CONR10R11, —COOR10, —SO2R10, —SO2NR10R11, —SO3R10, —NR11COR10 or by —NR11COOR10, wherein R10 and R11 are each independently of the others hydrogen, CrC8alkyl, C5-C12cycloalkyl or C2-C8-alkenyl; and to their use for color filter production and to color filters comprising said pyrimido[5,4-g]pteridine derivatives of formula (I).