[en] Highlights: • Novel precursors were prepared by dilithiozirconocene complex and chlorosilanes. • Zr/Si/C/O ceramics were obtained by pyrolysis of polyzirconocenesilane precursors. • The lightweight ceramic foams maintained the cellular structure up to 1800 °C. • The foamed ceramics also displayed good electromagnetic wave absorbing capability. A brand-new way to diverse Zr/Si/C/O preceramic polymers from dilithiozirconocene complex and chlorosilanes was designed for the first time. This simple route was fulfilled in normal pressure and at room temperature, without heating, cooling, pressurizing or electrolyzing. The pyrolysis of polymers and crystallization of polymer-derived Zr/Si/C/O ceramics were investigated by a combinational characterization of TGA, XRD, TG-FTIR, TG-GC-MS, SEM and EDS. By such polymers, Zr/Si/C/O ceramic foams with 3D networks were obtained at 1000 °C. The specific surface area of such ceramic foams was 78.18 m²/g, while the pure skeleton density and geometrical density were as low as 1.66 and 0.056 g/cm³. Interestingly, such ceramic foam showed fair thermal stability, whose cellular structure and mesoporous microstructure could maintain from 1000 °C to 1800 °C. Also, such non-ferrous materials performed attractive wave-absorbing properties at tunable frequencies from 15 GHz to 4 GHz, with maximum reflection loss of − 39 dB (1000 °C) and − 37 dB (1800 °C). These lightweight mesoporous Zr/Si/C/O ceramic foams with wave-absorbing and heat-resisting properties are promising candidates for high-temperature absorbents.