Diazonium surface treatment chemistry for Carbon Black and color pigments, invented and developed at Cabot is further expanded by including certain very reactive diazonium compounds, based on electron-deficient heterocycles. Increased reactivity of these molecules vs. aromatic amines significantly expands the range of treatable pigments and provides many choices in generation of InkJet and other high-performance pigment dispersions. Synthetic flexibility of combining a heterocycle with a functional group leads to large number of surface functionalization opportunities.