Abstract: This invention provides methods and devices for identifying and/or characterizing interactions involving molecules, including, but not limited to, identifying and/or characterizing interactions involving target molecules and candidate molecules. The present invention provides methods using multidimensional infrared spectrographic techniques, such as four wave mixing and pump-probe techniques, for identifying interactions involving biomolecules and therapeutic candidate molecules, and for characterizing such interactions in terms of their binding coefficients and/or equilibrium constants.