Highly stable organic radicals have garnered significant interest due to their potential applications in functional materials. Despite their unique electronic configurations, the practical use of organic radicals has been limited by synthetic challenges and low stability under various conditions. Previously, we reported the synthesis of N-heterocyclic carbene nitric oxide radicals (NHCNOs) and 1,2-dicarbonyl radical cations via direct NO gas or oxalyl chloride addition to N-heterocyclic carbenes (NHCs). While these radicals exhibited high stability in water and under harsh conditions, their redox stability remained limited. Herein, we introduce a multi-redox-active NHCNO stabilized by an acenaphthene-based carbene and a 1,2-dicarbonyl radical cation stabilized by a naphthoquinone-fused carbene. Leveraging these radicals, we are actively exploring their potential applications in biological systems such as stimuli-responsive NO donors or organic radical MRI contrast agents.