The use of conducting polymers to develop colloidal hollow spheres with uniform, controllable sizes and smooth surface is examined. PPy and PAni were selected as two typical examples for the proof-of-concept experiments due to their established use in a broad range of applications. When an oxidant is introduced into the suspension, polymerization will immediately occur on the surface of each PS template, generating a uniform shell of the conducting polymer. Nanometer-sized particles tend to circulate in the blood stream for a longer period of time than their micrometer-sized counterparts, offering a wider time window for imaging. Therefore, preparation of nanometer-sized hollow spheres is also an emerging subject of interest. The PAni coatings exhibited a relatively smooth surface, with the sample derived from a lower aniline concentration being smoother at the surface.