Global warming, climate change and our over-dependence on non-renewable fossil fuels demand long-term solutions to reduce CO₂ emissions and develop sustainable energy technologies. The electrochemical CO₂ reduction has the potential to accomplish a “carbon-neutral energy cycle”, which incorporates CO₂ as the unlimited carbon source for the production of high-density fuels, and renewable energy as the driving force behind the process.[1] However, for an industrial application, there are still challenges to overcome, such as low selectivity, short durability and low current densities along with high overpotentials. New sustainable, modular, robust and efficient catalytic platforms are needed. In this regard, this work entails a fundamental understanding of the CO₂ mechanisms using Single Atom Catalyst (SAC) within Covalent Organic Frameworks (COFs). This work focuses on the investigation of the electrochemical CO₂ reduction (CO₂RR) in water using new Manganese based-Covalent Organic Frameworks with emphasis on understanding the relationship between structure and electrocatalytic activity. The initial center of interest was to accomplish active performance and durability for CO₂RR using highly-organized {Mn(CO)₃} active sites within COFs. The catalytic activity of the materials was benchmarked against other molecular supported catalysts reported in the literature. Compared to equivalent Mn derivates, COFs exhibited higher selectivity and activity towards CO₂ reduction [2]. Additionally, mechanistic studies based on in situ / in operando spectroelectrochemical techniques (ATR-IR, UV-vis, SEIRA, EPR) together with DFT calculations were used to detect key catalytic intermediates and correlate the catalytic activity with the mechanical constraints impose to the {Mn(CO)₃} active sites by reticular framework. Of particular note is the detection of a radical intermediate within a Mn based COFs avoiding the detrimental formation of a dimeric specie determined as a resting state in the catalytic cycle. In addition, the study of the Mn centers within the COF was expanded and focused on the understanding of the mechanism and dynamic processes at the electrode interface. This study show case the richness and complexity of reticular materials and can serve as a guide to investigate the dynamics of these organic frameworks.