Disclosed is a process which comprises (a) dispersing into a solvent (i) toner particles comprising a resin and an optional colorant, and (ii) monomers selected from pyrroles, thiophenes, or mixtures thereof; and (b) causing, by exposure of the monomers to an oxidant, oxidative polymerization of the monomers onto the toner particles, wherein subsequent to polymerization, the toner particles are capable of being charged to a negative or positive polarity, and wherein the polarity is determined by the oxidant selected.