LAUSR

Metal‐cyanoquinone complex shows great potential in various applications due to its unique molecular structure and physicochemical properties, but has not been reported in electromagnetic protection (absorption and shielding) field. In this work, a series of metal‐cyanoquinone complexes including Cu‐TCNQ, Cu‐DCNQI, and Ag‐DCNQI is first synthesized, and then their electromagnetic protection behaviors are systematically investigated. The results suggest that Cu‐DCNQI shows better electromagnetic wave absorption (EMA) performance compared to Cu‐TCNQ and Ag‐DCNQI, where its maximal absorption reaches −33.2 dB under ultrathin thickness of 0.9 mm with a filler‐loading ratio of 20 wt%. Experimental results and first‐principles calculations indicate that Cu‐DCNQI exhibits good electrical conductivity and narrow bandgap, which are considered to be the main two reasons for its excellent EMA performance. Interestingly, when the filler‐loading ratio of CU‐DCNQI increases to 40 wt%, it shows excellent electromagnetic wave interference (EMI) shielding effectiveness (SE). Under the ultrathin thickness of 0.08 mm, its EMI SE exceeds 10 dB in the X‐band, and the maximum SE reaches 76.8 dB at 8.4 GHz. This research broadens the application scope of metal‐cyanoquinone complexes, and provides a new platform for the design and development of novel ultrathin electromagnetic protection materials.