Ionanofluids (INFs), ionic liquids (ILs) containing dispersed nanoparticles, show fascinating thermophysical properties. The amount of dispersed nanoparticles influences the properties of the base IL, allowing for a fine-tuning of the properties of the resulting INF. Even though INFs have been studied for more than a decade now, sufficient and reliable data are still lacking. The aim of this work is to report on the heat capacity, viscosity, melting temperature, and electrical conductivity of INFs based on 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide as a function of multi-wall carbon nanotube compositions. In this work, mathematical gnostics has been also used to estimate the uncertainty in each measured property. Moreover, a robust linear regression along a gnostic influence function was used to find the best curve fit for the measured data.