Understanding on the spectroscopic properties of a functional group is essential to use it to detect changes in the structural and/or dynamical properties through the situations of intermolecular interactions. The present study is devoted to elucidating the factors that control the solvation-induced changes in the C equivalent to N stretching frequency and the C-13 and N-15 NMR chemical shifts of the nitrile group. It is shown that the nonelectrostatic contribution of the hydration-induced changes in the C equivalent to N stretching frequency as previously thought, as well as the specific effect of hydrogen bonding on the C-13 and N-15. chemical shifts, actually originate from the spatially inhomogeneous nature of the electrostatic situation generated by the hydrogen-bond donating water molecule, especially by the OH bond dipole. On this basis, a unified electrostatic interaction model that encompasses the cases of both hydration and dipolar solvation is constructed. The responses of electrons in these two cases are also discussed.