We report the data of liquid density, thermal properties including glass transition temperature, melting point, and decomposition temperature, surface tension, and shear viscosity for imidazolium-based dicationic ionic liquids with the anions of bis(trifluoromethylsulfonyl)amide, bis(pentafluoroethylsulfonyl)amide, tetrafluoroborate, and nitrate. To find the unique and general features of the dicationic ionic liquids, data of their corresponding monocationic ionic liquids are also summarized. The results of the dicationic ionic liquids showed that the density was high; the glass transition temperature and melting point were high, and they were thermally stable. Also the surface tension was large, and the shear viscosity was high in comparison with the reference mono cationic ionic liquids. The data of the physical properties including liquid density, surface tension, and shear viscosity of the ionic liquids were also compared with that of alkanediols and alkyl alcohols to find the alkyene-linker and alkyl-group dependences in the ionic liquids and alcohols.