The growing demand for nano-structured composite materials and sustainable processes for next generation CO2 capture technologies has necessitated the need to develop novel and cost-effective synthetic routes for solid CO2 adsorbents based on hypercross-linked polymers (HCPs) and reduced graphene oxide (RGO) microporous sorbent materials with improved physico-chemical properties. The most important selection is modification of the synthesized microporous sorbent materials by the incorporation of RGO, giving rise to composite materials that combine the properties of both. These hybrid materials will be of great potential for carbon capture and storage (CCS) applications, especially for post-combustion CO2 capture, owing to the increase in CO2 capturing efficiency and selectivity to CO2 compared to other flue gases. Herein, we report a facile and effective approach for fabrication of HCPs-supported reduced graphene oxide composites. The microporous HCPs was synthesized using 4,4′-bis(chloromethyl)-1,1′-biphenyl monomer by Friedel–Crafts alkylation. The RGO was prepared by modified Hammers method. The as-synthesized composites were characterized by TEM, SEM, FTIR, TGA and N2 adsorption–desorption isotherm. The HCP/RGO composite showed maximum CO2 adsorption of 5.1 wt% than the HCPs alone at 40 °C and 1 atm.