Thermophysical properties including density (rho), speed of sound (u), specific conductivity (kappa), and refractive index (n(D)) for binary mixtures of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15) K. Further the excess molar volume (V-E), deviations in isentropic compressibility (Delta K-S), deviation in specific conductivity (Delta kappa), deviation in molar refractive index (Delta R), and partial molar quantities, viz., partial molar excess volume (V-i(E)), and partial molar deviation in isentropic compressibility (Delta K-S,K-i), have also been evaluated. In order to gain insight into molecular interactions taking place between different components of the binary mixtures, spectroscopic properties, viz., FT-IR and H-1 and C-13 FT-NMR spectroscopy of these binary mixtures, have been measured and analyzed. The measured thermophysical parameters and their excess values have been used to interpret the structural and interactional behavior of studied formulations. It has been seen that V-E, Delta K-S, Delta(kappa), and Delta R results are in agreement, which confirms that the addition ofa number of oxyethylene groups in Tritons and a rise in temperature resulted in stronger intermolecular interactions. FT-NMR and FT-IR results reveal that interactions are mainly taking place via pi-pi stacking between two rings of both components.