A diketopyrrolo-pyrrole compound according to Formula (I): ##STR00001## wherein R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, a halogen atom, a methyl group, an ethyl group, an tert.-butyl group, a phenyl group, a cyano group, and an acid group; R.sup.4--, R.sup.5, and R.sup.6 are independently selected from the group consisting of hydrogen, a halogen atom, a methyl group, an ethyl group, an tert.-butyl group, a phenyl group, and a cyano group; and wherein one of R.sup.7 and R.sup.8 is a group including two acid functions while the other one of R.sup.7 and R.sup.8 represents hydrogen. Pigment dispersions, methods for forming pigment dispersions, and use of the diketopyrrolo-pyrrole compound may include Formula (I).