We present an unprecedented and systematic route to controllably fabricate hexagonal, non:close-packed (hncp) monolayer colloidal crystals and binary colloidal crystals (BCCS)based on plasma-electron coirradiation of polystyrene colloidal monolayers followed by thermal, decomposition.. Hncp colloidal crystals with tunable particle sizes and periods could be fabricated by changing the pristine colloidal particle size and the thermal decomposition time. In addition, BCCs and trimodal colloidal crystals that are composed of different sized colloidal particles can also be fabricated by adding small particles on the prepared hncp colloidal crystals. Both the particle size ratio and the volume fraction of the BCCs can be widely tuned. These hncp colloidal crystals and BCCs have various potential applications as optical and photonic materials as well as in catalysis and sensors.