Diazine and triazine (and their N-oxides) possess an untapped potential to act as nitrogen-rich building blocks. Products arising from reactions of these azines are valuable N-heterocycles that provide privileged scaffolds for life science and for functional materials. The CASINOS project aims at exploring the frontiers of diazine and triazine (and their N-oxides) reactivities in earth-abundant metal- and/or organocatalytic processes. We will combine experimental and theoretical approaches to take advantage of their under-explored reactivity in nucleophilic reactions, as well as different types of cycloadditions. Specifically, we will tackle: 1. Reactivity We will investigate new frontiers for ionic and pericyclic reactions of diazines (1,3- and 1,4-) and triazine (1,2,3-) N-oxides. Inter- and intramolecular reactions will be studied with a focus on the reactivity differences between the oxidized and non-oxidized precursors. This initial study will lead to a sound understanding of reactivity for the development of catalytic process that will be addressed next. 2. Selectivity Catalytic inverse-electron demand Diels-Alder (IEDDA) cycloadditions are challenging in general, and some methodological gaps still need to be addressed in the case of diazines and triazines. Supported by preliminary results, earth-abundant metal- and/or organophoto- and organo-catalysis approaches will be studied not only to positively impact the rate and selectivity issues of the ionic and pericyclic processes but also to tackle high-risk, high-gain enantioselective associated transformations of these azaarenes. 3. Mechanisms We will gather fundamental knowledge on the mechanisms by combining experimental studies and theoretical investigations to support a rational design of new transformations as well as a pre-selection of potentially useful starting materials.