Owing to their unique composition, DES are promising solvating environments, affecting the structure and self-assembly of solutes. For example, the self-assembly of sodium dodecyl sulfate (SDS) in DES has recently been studied, implying DES can form microemulsions different from those in water. In another case, the solvation of the polymer polyvinylpyrrolidone (PVP) in DES is distinct from water, whereby the DES appear to be a better solvent for the polymer. It has been also shown that depending on state of matter of the solute homogeneous or heterogeneous mixtures are formed.