In the present study 1.0, 2.0 and 4.0 wt. %Al was added with the Sn-8Zn- 3Bi eutectic alloy to investigate the effect of Al as a fourth element on the microstructural and mechanical properties of the newly developed quaternary alloys. The solidification behavior of the quaternary alloys with the cooling rate was also investigated as well. The results indicated thatAl refined the microstructure and formed intermetallic compounds with the quaternary alloy. The microstructures of newly developed quaternary Sn- 8Zn-3Bi-xAl alloys had fine needle-like á-Zn phase with some IMC dispersed in the â-Sn matrix. The compact shaped IMCs uniformly distributed in the â-Sn phase which resulted in an increase in the mechanical properties, due to the second phase dispersiod strengthening mechanism. As the Al content increased, both the microhardness and macrohardness of the Sn-8Zn-3Bi-xAl quaternary alloys improved due to the presence of harder IMC in the microstructure. With further employing faster cooling rate, the mechanical properties were also promoted.