The objective of this article is to use the quantum chemistry tools coupling calculations without of-balanced green functions for the simulation of transport properties of conjugated organic systems already explored or during Summary grafted on driver's gold or carbon electrodes within metal junctions. The goal is to access to structural, electronic and spectroscopic information, to the curves of the variation of the conductance as a function of the metal-molecule coupling, the length of the system, and the nature of the electrodes. In the first part, all the methods and methodology used to implement the Fisher-Lee approach as well as the use of the DFT to optimize geometries are introduced