“…Room-temperature ionic liquids (ILs) are fascinating molten salts composed solely of ion species with distinct molecular symmetry and charge delocalization, having their melting points below 100 °C. − Recent years have seen a great enthusiasm for ILs regarding their utilities as facilitating functional materials in diverse applications including material synthesis and catalysis, , microlubrication and nanotribology, , gas adsorption and separation, , and electrochemical devices for energy storage and harvesting. ,,, Among the whole IL community, imidazolium ILs hold peculiar significance because of their multifaceted physicochemical characteristics, such as low volatility and flammability, reasonable viscosity–conductivity features, high thermal- and electrochemical-oxidative stabilities, wide electrochemical windows, and exceptional affinities to molecular compounds having varied polarities. − ,, These remarkable properties of imidazolium ILs are intrinsically correlated with inherent ion structures and delicate interactions among constituent ions at the nanoscopic level. ,,,, Therefore, the microstructural and dynamical quantities of ion species, the self-assembled mesoscopic liquid morphologies, and the macroscopic functionalities of imidazolium ILs can be widely tuned via a judicious selection of ion moieties, an introduction of a controllable amount of molecular solvents (solutes) into IL matrices, and a specific mutation of constituent ions with atoms and molecular groups to meet specific requirements in diverse applications. − …”