Mixing dynamics of liquid diethyl ether and chloroform were studied by time-resolved Fourier-transform infrared absorption spectroscopy in attenuated total reflectance mode (ATR-FTIR). An in situ experiment where chemicals were mixing in the vertical cell directly attached to the diamond ATR accessory was carried out. The data were analyzed by two-dimensional correlation spectroscopy (2D COS) and multivariate curve resolution (MCR). The analysis of ATR-FTIR spectra has shown that each species (diethyl ether and chloroform) exist in an unbound (free) state and bound state (as a part of the molecular complex). The concentration and spectral profiles of mixture components were obtained using MCR decomposition. A theory of nonlinear diffusion has been used to model the experimentally obtained concentration profiles. It has been shown that the theoretical concentration profiles are in good qualitative agreement with experimental ones.