A review of the scarce literature on the use of entirely liquid mixtures of ionic liquids and polymers in a solvent role is presented. These mixtures can present interesting characteristics such as very low volatility, good solvation ability, and tunable physical and thermal properties, and they can be especially attractive as solvent systems for carrying out reactions or separations. The liquid polymer and ionic liquid can be miscible, or can exhibit immiscibility, thus giving rise to totally liquid, biphasic systems. Novel systems of the latter kind, constituted by 1-alkyl-3-methylimidazolium chlorides or acetates and poly(alkylene glycol)s such as poly(ethylene glycol) or poly(propylene glycol), are reported herein. Fundamentals of their liquid-liquid equilibrium are described. (C) 2010 Elsevier B.V. All rights reserved.