Syntheses are reported for ionic liquids containing 1-methyl-3-octylimidazolium or 1-butyl-4-methylpyridinium cations and trifluoromethyl sulfonate, dicyanamide, bis(trifluoromethylsulfonyl) imide, or nonafluorobutyl sulfonate anions. Densities, melting points, glass-transition temperatures, solubilities in water, and polarities have been measured. Ionic liquids containing pyridinium cations exhibit higher melting points, lower solubility in water, and higher polarity than those containing imidazolium cations.