Four room-temperature ionic liquids (RTILs) based on N-methyl-N-methoxyethylpyrrolidinium (PYR12O1 +) and fluorinated sulfonylimides, bis(fluorosulfonyl)imide (FSI−), bis(trifluoromethanesulfonyl)imide (TFSI−), bis(pentafluoroethylsulfonyl)imide (BETI−) and (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl)imide (IM14 −) anion have been synthesised and intensively investigated from an electrochemical and physico-chemical point of view, including thermal behaviour, viscosity, conductivity and electrochemical stability. The prepared ionic liquids are thermally stable (over 200°C in N2 and over 180°C in O2 atmosphere) and electrochemically stable with electrochemical stability windows on platinum in the range from 4.7V (PYR12O1FSI) to 5.4V (PYR12O1IM14). Conductivity decreases in the series FSI-TFSI-BETI-IM14 according to the viscosity increase. DSC measurements showed no crystallisation down to −150°C for PYR12O1TFSI and PYR12O1IM14.