The densities and conductivities of the binary mixtures of 1,2-dimethyl-3-hexylimidazolium bis(trifluoromethylsulfonyl)imide ([DMHIM][Tf(2)N]) and dimethyl carbonate (DMC) were measured at temperatures of (293.15 to 333.15) K. The densities increase with an increase in the concentration of [DMHIM][Tf(2)N] or a decrease in the temperature. The excess molar volumes V(E) were calculated and fitted to the Redlich-Kister equation. The conductivity increases sharply to a maximum value when the concentration of [DMHIM][Tf(2)N] is increased and decreases quickly after the maximum. The data obtained will be helpful for the application of the ionic liquids as electrolytes and also useful for the ionic liquids database.