Temperature dependent viscosity, conductivity, and density data of binary mixtures containing ethylene carbonate (EC) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide (EMIM-TFSA) were determined at atmospheric pressure in a wide temperature range of (20 to 120) °C. Additionally, differential scanning calorimetry (DSC) measurements were performed from (−120 to +100) °C to characterize phase behavior of the mixtures. On the basis of the experimental data it is demonstrated that the lattice hole theory can be applied excellently to the conductivity data of the binary mixture EMIM-TFSA/EC. The viscosity data were fitted according to the Vogel–Fulcher–Tammann–Hesse (VFTH) equation and analyzed with the help of the fractional Walden rule. It is concluded that the mixtures can be classified as fragile according to ionicity. The aim of the study is to present fundamental physicochemical data about the mixtures as a basis for structure–property relationship-calculations of solvent mixtures or use as electrolytes for various applications.