Porous liquids (PLs) are defined as liquids that contain permanent microporosity -they can be neat systems where the porosity originates in the liquid porogen itself (type I), solutions of porogens dissolved in a cavity-excluded solvent (type II), or dispersions of porogens dispersed in a cavity-excluded solvent (type III). Porous ionic liquids (PILs) are a sub-class of PLs which incorporate ionic liquid (IL) functionality, whether that is on the pore carrier itself or as the solvent, 2 and offer certain advantages, not least the negligible vapor pressures of most systems.