This research presents the synthesis of a novel three-dimensional (3D) hybrid nanostructure comprising polyaniline (PANI) grafted onto a matrix of graphene oxide-multi-walled carbon nanotubes (GO-MWNT). The hybrid nanostructure was prepared to exploit the synergies of graphene, carbon nanotubes, and PANI. The composite was synthesised by grafting PANI onto the GO-MWNT matrix using an in situ oxidative polymerization route. The study primarily focuses on the synthesis process, physicochemical characterization, and dielectric property analysis of the resultant hybrid material. Structural order, morphological properties, and thermal properties were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dielectric properties were comprehensively analysed through dielectric measurements. For dielectric measurements, the composite powder was compressed into pallet form with a 1 mm thickness and an 8 mm diameter. Specific resistivity, dielectric constant, and tangent loss were recorded with frequency at room temperature.