In this work we present a summary of our obtained results in this last decades concerning analysis of the charge density distribution in a variety of organic industrial compounds used in different areas such as telecommunications, solar energy or biology. It is known that some physical properties such us the non-linear optical response and the biological activity of the studied compounds are directly linked to their electronic molecular structure. The knowledge of the electron density function derived from x-ray high diffraction studies combined to theoretical ab-initio calculation can lead...