In a mechanic molecular switch, electron transfer processes are controlled by a conformation change of the molecule induced by the move of one of its part. The change in through ligand electronic coupling induced by the displacement or the rotation of benzene ring(s) included in a non saturated ligand are discussed. This change is used to build a flip‐flop switch constituted of an isomerizable handle connected to a bis 1,4(4 pyridyl ethynyl) benzene ligand. Isomerization of the handle produces a rotation of the central benzene. Calculated energetic and electron transfer properties of this switch are presented.