With the advent of intelligent society and the popularity of electronic equipment, the protection and treatment of electromagnetic (EM) radiation have become hot research topics all over the world. Herein, novel 2D carbon‐based nanoplates with uniformly embedded Co nanoparticles are prepared, with unique hierarchical structure and integrated magnetic‐dielectric components. The obtained hierarchical nanoplates exhibit a wide range of tunable EM properties (ε′ for 3.38 to 34.67 and ε″ for 0.13 to 31.45) by manipulating the dispersed states inside wax system, which can achieve an effective switch from microwave absorption to EM interference shielding performance. The optimal reflection loss reaches −55.6 dB, and the shielding efficiency is 93.5%. Meanwhile, the hierarchical nanoplates also exhibit impressive capacitive performance, with a specific capacitance of 1654 F g−1 at 1 A g−1. Based on this, a creative device is constructed with the nanoplates, which can convert harmful EM radiation to useful electric energy for recycling. This work offers a new idea for the development of EM materials and functional devices, powerfully promoting the advance of energy and environmental fields. Novel 2D carbon‐based nanoplates with uniformly embedded Co nanoparticles are prepared, with highly tunable electromagnetic properties and excellent electrochemical performance. Based on this, a creative energy conversion device is constructed, which can convert harmful EM radiation to useful electric energy for recycling. This work offers a new horizon for the development of advanced electromagnetic materials and functional devices.