Preparation and characterization of isolated particles and clusters of carboxylic acid-terminated polystyrene (CPS) and poly(4-vinyl pyridine) (P4VP) blends in chloroform/methanol (9/1, v/v) solution are reported. In chloroform CPS-P4VP blends form graft-like structure due to the interaction between terminal carboxylic acid and 4VP units. Upon addition of methanol, isolated particles and clusters with micelle-like structure were prepared. Dynamic light scattering (DLS) results and transmission electron microscopy (TEM) images both suggest the existence of isolated particles and clusters with micelle-like structure in the mixed solution. The effects of weight ratio of CPS to P4VP and addition of copper ion on the size of isolated particles and clusters were also investigated.