Graphene reinforced copper based metal matrix composites have emerged as favorable materials for innovative heat sink applications due to their extra-ordinary thermal properties. This research paper presents the thermal behavior of copper matrix based composites for applications in heat sink. The composites were synthesized through pressure-less sintering and graphene powder was used as reinforcement. The composite specimens were tested for their density and hardness. The homogeneity of the composites was examined through microstructure examination using scanning electron microscopy (SEM), the phase determination was done using X-ray diffraction (XRD) technique. SEM micrographs revealed that the mixing of powders was quite homogeneous and no agglomeration could be seen. The synthesized composites were tested for their density, hardness and thermal conductivity. The density of the composite samples was found to decrease with the increase in graphene concentration while hardness exhibited an increasing trend. The thermal conductivity of the composite containing 2.0 wt.% graphene exhibited highest thermal conductivity of 401 W/m–K.