The capability of electrocatalytic reduction of carbon dioxide (CO2) using nitrogen (N)-doped carbon strongly depends on the N-doping level and their types. In this work, we developed a strategy to generate mesoporous N-doped carbon frameworks with tunable configurations and contents of N dopants, by using a secondary doping process via the treatment of N,N-dimethylformamide (DMF) solvent. The obtained mesoporous N-doped carbon (denoted as MNC-D) served as an efficient electrocatalyst for electroreduction of CO2 to CO. A high Faradaic efficiency of ∼ 92% and a partial current density for CO of −6.8 mA·cm−2 were achieved at a potential of −0.58 V vs. RHE. Electrochemical analyses further revealed that the active sites within the N-doped carbon catalysts were the pyridinic N and defects generated by the DMF treatment, which enhanced the activation and adsorption CO2 molecules. Our study suggests a new approach to develop efficient carbon-based catalysts for potential scalable CO2RR to fuels and chemicals.