In this proposal, we are discussing the opportunity of studying the electron transfer reactivity of divalent organolanthanides complexes. This type of complexes has known a growing attention in the last few years and few groups around the world contributed to the description of intriguing reactivity as well as singularities in electronic structures. The latter have been challenged by spectroscopic observations that are not in agreement with the traditional believe of pure electrostatic bonds but are also far from a classical covalent model. A better understanding of the overall bonding picture may be overcome by making new divalent lanthanides with simple ligands, typical of organometallic chemistry, such as the indenyl ligand or amides based ligands, and divalent lanthanides precursors. We will be engaged in making new divalent molecules with the classical Sm, Eu and Yb lanthanides but also the more challenging Tm, Dy and Nd. The divalent lanthanides complexes are extremely reactive toward – even weak, oxidants. We will take advantage of having stable divalent complexes to study the single electron transfer from the reactive divalent metal to redox non-innocent ligands such as N-aromatic heterocycles and P-aromatic heterocycles. Characterization of these complexes will be performed with routine experimental techniques of synthetic organometallic chemists (such as X-ray diffraction, multi- atomic NMR, absorption visible spectra, IR, electrochemistry and magnetic studies) but we are also interested in this project to have a deeper look at their electronic structure using optical spectroscopy measurments, almost an empty field of research for organolanthanides. As to reinforce the expected experimental observations, a strong feedback from theoretical chemistry is proposed in the enclosed document in order to gather as much details we may and lean toward a decent physical model. If some of the complexes considered in this proposal are expected to be stable to allow their isolation; further reactivity is also expected and examples of C-H activation and of reversible C-C coupling have been observed in our preliminary work. We would like to take advantage of such reactivity to react these molecules with small molecules such as N2, CO2 or N2O. Assisted with theoretical calculations of energy profile and by experimental kinetics, their reactivity will be carefully studied and aim at relating the main outcomes to the electronic structure of the parent molecules.