The refractive index (n) and density (ρ) are crucial physical parameters that are greatly influenced by the solution chemistry of liquids and their binary mixtures. Refractive index and density data for pure liquids are commonly found in literature, but information regarding mixtures is often limited or scarce. Therefore, in the present study, we report the refractive index (n) and density (ρ) of binary mixtures of n-Hexanol (n-HxOH) with N, N-Dimethylformamide (DMF) over varying concentration of composition at constant temperature 293.15 K. The measured data are utilized to evaluate various refractometric parameters, namely, molar volume (Vm), molar refraction (Rm), atomic polarization (PA), polarizability (α), molecular radii (r), and internal pressure (Pint) of the liquids and their mixtures. Deviation of molar volume (Δm), reduced free volume (Δ(Vm/Rm)), molecular radii (Δr), and internal pressures (Pint) are determined and fitted with Redlich–Kister polynomial to derive the binary coefficients and correlation coefficient. The nature of deviations of these parameters is discussed in light of hetero-molecular interactions between the participating molecules. Furthermore, a comparative study of Lorentz–Lorentz (L-L), Weiner (Wi), Eyring–John (E-J), Gladstone–Dale (G-D), Arago–Biot (A-B), Newton (Nw), Oster (Ost), and Eykman (Eyk) relations for predicting the refractive index of a liquid mixtures computed to validate the mixing models for the studied binary liquid mixtures over the whole concentration range of n-Hexanol (n-HxOH) with N, N-Dimethylformamide (DMF) at the constant temperature (293.15 K). Comparison of various mixing models with experimental values of refractive indices expressed in terms of Average Percentage Deviation (APD).