Ionic liquids with the weakly coordinating perfluoroalkoxyaluminate anions, Al(ORF)(4)(-), are obtained by a metathesis reaction of LiAI(ORF)(4) and [bmim]Cl or [bmpyr]Cl in high yields. The compounds [bmim][Al(hfip)(4)] and [bmpyr][Al(hfip)(4)] have surprisingly low viscosities at elevated temperatures (60 degrees C) and an exceptionally high electrochemical window, which might render them useful for certain applications.