A pigment dispersant comprising a graft copolymer is described. The graft copolymer comprises a backbone having polymerized vinyl imidazole groups and side chains from macromonomers. The vinyl imidazole comprises 2 percent to 20 percent by weight of the graft copolymer and the macromonomer comprises 55 percent to 85 percent by weight of the graft copolymer. The pigment dispersant is useful for forming pigment dispersions that can be used in solvent borne coating compositions.