Biodiesel has established itself as a precisely sufficient alternative fuel for diesel engines. Generators are vital equipment of industry and have a wide usage area in agriculture. Furthermore engine performance and emissions of electric generators gain importance due to their indoor applications. The objective of this study was to investigate the performance and smoke results of Bombax pentandrum and Cassia siamea biodiesel utilization in diesel engine. The smoke opacity test was conducted using 20% blends of biodiesel with Single cylinder, four stroke, air cooled, indirect injection diesel engine, and generator performance tests were performed using 10% blends in a 7.5 KVA (6KW) electrical generator. Consecutive tests on Diesel fuel, B20 and B10 blends of Bombax pentandrum and Cassia siamea methyl ester were conducted, and the results were compared with each other. When compared to Diesel fuel, both utilizations showed improved results on engine performance and emissions. According to the result obtained, Bombax pentandrum and Cassia siamea seed oil originated biodiesel can be utilized as a blend component during generator applications in rural areas and indoor applications.