The research presented in this thesis makes use of theoretical/computational techniques to calculate nonlinear spectroscopic signals and molecular volumes. These techniques have become more practical with advances in computational resources and now are an integral part of research in these areas. Preliminary results allude to the power of these techniques when applied to relevant problems and suggest that much progress can be made in understanding the complex nature of nonlinear spectroscopic signals and molecular volume contributions. The nonlinear spectroscopy work involves writing the quantum mechanical response functions in terms of classical time correlation functions which are amenable to calculation using classical molecular dynamics. The response functions reported in this thesis include the fifth order response function, probed in the fifth order Raman experiment, and the third order response function probed in the two dimensional infrared experiment. The molecular volume calculations make use of modern algorithms used in molecular dynamics simulations to calculate the full thermodynamic volumes of molecules.