The set contains experimental data for 12 different properties: melting point, glass transition temperature, thermal decomposition temperature, viscosity, density, heat capacity, CO2 capacity, electrical and thermal conductivity, cytotoxicity towards the leukemia rat cell line IPC-81, surface tension and refractive index. The accompanying PDF file contains the literature references from which the data has been obtained. The structures for all the cations and anions are provided in the SMILES format.