This proposal aims to study the interactions within a prototypical ionic liquid / co-solvent system. Such systems are currently under investigation as potential solvating media for biomass (e.g. cellulose) reprocessing, wherein the ionic liquid provides the strong interactions required to solvate such difficult to dissolve natural polymers, and the co-solvent serves to reduce the viscosity of the overall system. The use of co-solvents for ionic liquids is also commonplace when performing NMR studies on ionic liquid systems, since usage of the neat ionic liquid is impractical. Many contrary viewpoints exist in the literature as to the interactions present between the co-solvent and the ionic liquid, ranging from "no significant interaction" to "full ionic separation of the ionic liquid". The present experiment aims to clarify the interactions present in these systems.