In this article the volumetric behaviour of the nanostructured liquids, butyltrimethylammonium bis(tri fluoromethylsulfonyl) imide and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl) imide, is reported. Density was measured in the temperature range (278.15-398.15) K up to 120 MPa with a high pressure densimeter based on the vibrating tube principle. Experimental densities were correlated as a function of temperature and pressure by means of the Tammann-Tait equation obtaining standard deviations lower than 3.5 x 10(-4) g.cm(-3). In addition, the isobaric thermal expansivity and the isothermal compressibility have been calculated from the Tait-like correlation. Furthermore, two group contribution methods proposed by Gardas and Coutinho and by Jacquemin et al. were applied to these fluids to analyse their prediction abilities for the high-pressure density. (C) 2017 Elsevier Ltd.