An experimental analysis of pool boiling is conducted on the GNP/Cu-Al2O3 (GNP-graphene nano particle) nanocomposite coated copper surfaces at atmospheric pressure using DI (distilled water) as boiling fluid. A two-step electro-deposition technique is used for fabrication of these micro/nano porous coated surfaces. A modified surface structure is formed due to this deposition and various surface morphology parameters such as surface structure, roughness, wettability are analysed. Results show the enhancement in BHTC (boiling heat transfer coefficient) and CHF (Critical heat flux) in nano composite coated surfaces compare to the bare copper surface. The maximum CHF of 2415 (kW/m2) and BHTC of 171.28 (kW/m2K) is found in the NCCS (nano-composite coated superhydrophilic) surfaces which are 122% and 239% more than the bare copper surfaces. The boiling performance is augmented mainly because of the improvement in roughness, wettability and also for the high thermal conductivity of the GNP/Cu- Al2O3 nano coating. Quantitative study of the bubble dynamics like active nucleation site density, bubble emission frequency, departure diameter of bubbleand their impact on heat transfer performance in the case of NCCS surfaces is performed with high-speed visualization.