Two-dimensional (time-frequency) ultrafast IR vibrational echo experiments were used to investigate solute-solvent interactions in solution. The experiments were performed on symmetric (S) and antisymmetric (A) CO stretching modes of (acetylacetonato) dicarbonylrhodium(I) in dibutylphthalate (DBP) at 150 K. The two-dimensional (2D) spectrum displays quantum beats at the nominal frequency difference between the S and A modes. However, as the observation wavelength is moved to higher energy: the quantum beat frequency decreases. The change in frequency is related to the nature of the solute-solvent interactions. Model calculations indicate that interactions with the solvent result in CO local mode frequencies that are strongly correlated.