Densities (rho), speeds of sound (u) and refractive index (nu) for the binary mixture of 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim] [NTf2] with N-Vinyl-2-pyrrolidinone (NVP) over the entire range of composition and at temperatures ranging from 298.15 K to 323.15 K at 0.1 MPa pressure, are reported in this investigation. From the experimental data, excess molar volumes (V-m(E)), excess molar compressibilities (k(s)(E)), excess molar isentropic compressibilities (K-s,m(E)), excess speeds of sound (u(E)), and deviation in molar refraction (Delta R-m) are calculated and fitted with Redlich-Kister polynomial smoothing equation. Excess molar volumes are predicted through PFP theory and the results are compared with experimental findings (C) 2017 Elsevier Ltd.