Carbon-based electromagnetic interference (EMI) shielding materials have witnessed a fast evolution in recent years. But challenges of lightweight, flexibility, and good heat dissipation properties required to explore new EMI shielding materials. Herein, a unique SiC-based hybrid composite paper was prepared, as an advanced thermally stable and conductive material for boosting the EMI performance. In this study, a lightweight and flexible network structure of mesocarbon microbeads (MCMB) and multiwall carbon nanotubes (MWCNTs) with polyacrylonitrile (PAN) was developed and SiC was incorporated during the fabrication process or synthesized directly within the matrix structure. EMI shielding effectiveness (SE) of the hybrid composite papers was studied in the X-band frequency region and a maximum EMI SE value of -67 dB was achieved at a frequency of 10.3 GHz. In addition to EMI shielding properties, the hybrid composite paper shows high thermal stability and good thermal conductivity required for proper heat dissipation from the system accompanied by robust mechanical properties. These outcomes make SiC-composite paper attractive material for applications in the lightweight and flexible modern electronic devices with good heat dissipation characteristics