Capacitive deionization (CDI) has emerged as a promising way to obtain freshwater from saline water, but its implementation is in its infancy and remains challenging due to the low salt adsorption capacity (SAC) of commonly used activated carbons (ACs). It is thus desirable to develop carbon electrodes that can exceed the performance of ACs benchmarks. In this work, nitrogen-doped mesostructured carbon nanocrystals (NMCs) have been developed by direct carbonization of highly ordered mesostructured polymers. Due to their mesoporous structure, high N content and large surface area, NMCs exhibit a maximum SAC of 20.63 mg g(-1). This state-of-the-art carbon electrode largely surpasses common ACs. This work demonstrates the significance of the material synthetic chemistry and the importance of nanostructuring carbon materials for CDI applications.