In this communication, we will present recent results on the oxygen reduction reaction (OOR) on nitrogen doped carbons. DFT calculations on nitrogen doped graphene systems will be used to understand the key elements that activate the reaction on these materials. The study is centered on the monodentate chemisorption of molecular oxygen as the first step of the process. It will be shown that carbon atoms are the active sites provided that several conditions are fulfilled. First, water should be included in the models, since it stabilizes the adsorption of the oxygen molecule with the characteristics of a superoxide species on the carbon atoms, which are the active sites. This carbon atom should be able to transition from a sp² hybridization state to sp³ upon adsorption of the oxygen molecule to have a favorable interaction energy with the oxygen molecule. This transition is favored destabilized carbon atoms, that is, those neighboring a nitrogen dopant. Second, a significant charge transfer to this site should occur, so that charge can be concentrated on the adsorbed oxygen molecule. This charge transfer requires the presence of additional nitrogen dopants, which are charge donors, even when they are in distant positions. When the nitrogen dopant is located in an edge of the graphene structure, a clearly favorable chemisorbed state for molecular oxygen was found when nitrogen-dopant is hydrogenated and located at an armchair edge. The chemisorbed state is further favored by additional available charge from other nitrogen. By contrast, the chemisorbed state of oxygen is much less favorable when the hydrogenated pyridinic nitrogen-dopants are located at zigzag edges. To demonstrate the applicability of this approach, the ORR was experimentally studied on an aza-fused π-conjugated microporous polymer, which has a very well characterized structure. The experimental results using a rotating disk configuration indicate that hydrogen peroxide is almost exclusively produced at very low overpotentials on these materials. The DFT calculations indicate half of the nitrogen atoms of the material are hydrogenated at the potentials at which the reaction takes place. This hydrogenation process destabilizes some carbon atoms in the lattice and also provide a source of charge. On these carbon atoms, molecular oxygen could be chemisorbed with the aid of charge transferred from the hydrogenated nitrogen atoms and solvation effects, as in the previous cases. Due to the low destabilization of the carbon sites, the resulting molecular oxygen chemisorbed state is only slightly stable, promoting the formation of hydrogen peroxide.