This article is an attempt to develop Ni-based shielded metal arc welding electrodes to join SS304L austenitic stainless steel to P91 martensitic steel used in power plant applications. Nickel-based electrodes were prepared using a mixture design approach. Dissimilar welds of SS304L/P91 were fabricated using Nickel-based laboratory-developed electrodes and commercially available electrode (ENiCrFe-3). A comparison was drawn between the weld characteristics of commercial and laboratory-developed electrodes. Experimentation was performed to evaluate the microstructural changes and mechanical characterization which includes hardness profile, tensile strength, the impact strength of the base materials, as well as dissimilar welds. Welds fabricated with a laboratory-developed electrode possesses better weld quality and mechanical characteristics. A higher amount of Ni and Cr was observed in the laboratory developed electrodes as compared to the commercial electrode. © 2020, © 2020 Taylor & Francis.