Reducing agents with neutral organic structures and exceptionally negative redox potentials have received a renewed interest especially since the astonishing advances of their reactivity in organic chemistry. Strong organic electron donors (OEDs) are capable of spontaneous single- or double-electron transfer to organic substrates under mild and homogeneous conditions. The OEDs represent serious rivals to highly aggressive metal-based reducers and emerge as an attractive novel source of reducing electrons. Thus far, they have been scarcely studied and approaches involving OED-promoted electron transfer steps are not sufficiently exploited despite their synthetic potential and their tunability. Consequently, their application scope remains quite narrow. In this context, it is of utmost importance to fully master the chemistry of organic reducers and to establish their fields of application. To address the important shortcomings of their applications, this research proposal aims first at developing novel libraries of organic electron donors able to overcome current boundaries. More importantly, the preparation of air-stable precursors, easily in-situ activated, will extend their practicality. The development of OED-promoted redox catalytic cycles will further fulfill the need for atom-economy and latent approaches, often necessary in the manufacturing industries.Their structures will be diversified and evaluated in order to better understand the factors governing single- or double-electron transfer as well as their reducing power. The diversity of the synthesized donors will thus provide a privileged database to investigate the relationships between molecular structure and reactivity. The second aspect of the project will be dedicated to the exploitation of the OED-generated active species in the reduction of challenging substrates and to the exploration of unprecedented applications. A comprehensive study of their scope and limitations, as well as of the involved mechanism will supply chemists with an exhaustive guide of their capabilities and spread their application panel in radical chemistry. This also falls into a context of searching new reduction methodologies, combining efficiency, modularity and high selectivity, and following the requirement of the sustainable chemistry. Reduction reactions are much less mastered than the oxidative processes extensively used for the fabrication of many everyday objects. With the decline of fossil sources, it is urgent to develop alternative routes to these fundamental compounds. In addition, a special focus will be given to the domain of material chemistry through the use of organic electron donors as initiators of polymerization. We have demonstrated that OEDs represent an unique tool for efficient, simple and room temperature polymerization process, responding to energy-friendly, cost-efficient and secure technical specifications. Their high group tolerance makes them fully compatible with the synthesis of a large range of polymers of wide industrial importance. The additional reducible functional groups accessible with our novel series of organic electron donors will extend the process to the metal-free polymerization of a whole new range of monomers under mild conditions and without the need for co-initiators. To go further with this highly innovative process, a detailed comprehensive mechanistic study will help to i) understand the initiation and chain propagation pathways and ii) prepare optimized OED structures as polymerization initiators. This will illustrate their undeniable potential as efficient and versatile reagents to the scientific and industrial community. In term of social and economic benefits, the financial support of this project will allow us to collect the decisive results necessary to reach the high technology readiness levels required by the European research program Horizon 2020 and access to the pre-industrialization step of our concept.