ABSTRACT Innovative ionic liquids (ILs) can be prepared by properly combining pure ILs, thus obtaining materials with improved characteristics. For instance, three different mixture families, namely PYR11TFSI-PYR14TFSI, PYR11TFSI-PYR18TFSI and PYR14TFSI-PYR18TFSI, were prepared and investigated in terms of thermal behavior, ionic conductivity and ion self-diffusion coefficient as a function of the mole composition. The physicochemical properties, including mechanical consistency, of these mixed ionic liquids were found to be enhanced and/or finely tuned by properly varying the aliphatic chain length and/or the mole ratio of the pyrrolidinium cations. This issue might be profitably exploited to match the electrolyte requirements of electrochemical devices operating under particular or hard conditions, not always achievable by single materials.