The impact of incorporating various alloying elements (Se, In, Zn and Al) into Sn43Bi solder alloys was investigated. These components fundamentally changed the microstructure and thermal properties of the base alloy. For instance, the particle size of Sn43Bi decreased from 465.58 Å to 217.09 Å with the addition of 2 wt% In. With Sn43Bi2In showing the lowest contact angle of 21.5° compared to 23.34° for the base alloy, the contact angle, a gauge of wettability improved especially. With the addition of 2 wt%, In, thermal analysis showed that the melting temperature of Sn43Bi dropped from 139°C to 114°C, the pasty range closed from 10.4°C to 7.5°C. On the other hand, Al raised the pasty range and the melting temperature. These results show that particular alloying elements can maximize the mechanical and thermal characteristics of Sn-Bi solder alloys, so improving their suitability for electronic uses.