Water-soluble ionic liquids (IL) were used as reaction media to perform homogeneous polymerizations under microwave irradiation. The investigated reaction systems include the free radical polymerization of methyl methacrylate and the cationic ring opening polymerizations of 2-phenyl-2-oxazoline and 2-(m-difluorophenyl)-2-oxazoline. The incorporation of ILs into the polymerizations showed a more efficient heating profile of the reaction mixtures under microwave irradiation in comparison to the cases without ILs. Moreover, a convenient approach for the polymer isolation and recovery of the ILs for further polymerizations is demonstrated taking advantage of the water solubility of the investigated ILs. This synthetic approach is an alternative, efficient, and green method for the manufacture of hydrophobic polymers which may allow depletion of the emission of volatile organic compounds into the environment and for energy savings.