In this work, we have studied the changes in the Four-Wave Mixing spectroscopic signal response in the frequency space by propagation of the electromagnetic fields and intramolecular coupling effects. Firstly, in a propagation treatment at all orders in the pump field and first order in the probe and signal fields, we obtain a description of the Four-Wave Mixing signal. Secondly, for the inclusion of the intramolecular effects, the model is a generalization of the conventional two-level approach in that it includes a simplified description of the molecular structure. The Born-Oppenheimer electronic energy curves for this simplified molecular model consist of two intercrossing harmonic oscillators potential with different force constants. The transition and permanent dipole moments are critical quantities for this analysis in the frequency space of the local macroscopic polarization in the adiabatic representation when the rotating wave approximation is not considered.