A process for preparing a modified pigment having attached at least one organic group is described. This process comprises the step of combining, in any order, a colored pigment, an aromatic amine, a base, and an aqueous medium to form a mixture, and then combining the mixture and a diazotizing agent to form the modified pigment. The aromatic amine comprises at least two carboxylic acid groups, preferably being vicinal. The resulting modified colored pigment can be used in an inkjet ink composition to produce printed images having good overall properties.