This study is devoted to the development of lightweight Aluminum alloy to reduce energy consumption and environment pollution in automobile sector. Aluminum alloy shows impressive strength though they are lightweight. The effect of Cu on Al-5.5Zn-2.5Mg-xCu alloy has been studied and improvement in mechanical properties within a range has been observed. The optical microstructure confirmed the formation of Cu enriched brittle phase by solid solution strengthening and it accelerates the hardness and tensile strength. After certain limit strength followed the opposite trend so the material can be used as high strength material when the Cu content will be in a certain limit. In automobile sector vehicle parts made with this alloy material has less weight than commonly used steel. The total weight reduction of a vehicle will reduce the energy consumption which will ultimately eliminate the emission of environment pollutant gas.