This research focuses on reduce Nitrous oxide (NOx) and soot emissions while enhancing the efficiency of Compression Ignition (CI) engines by implementing the Reactivity Controlled Compression Ignition (RCCI) approach, which incorporates the use of low-reactive gasoline as a fuel source. The highly reactive biodiesel (BD) derived from Jatropha Curcas (JC) feedstock served as an ignition source for RCCI combustion. According to the research, when compared to BD blends, the combustion of RCCI resulted in improvements of about 0.2-1.2 for Brake Thermal Efficiency (BTE), 11.3-44.6 for Net Heat Release Rate (NHRR) at full load and 4.9-13.6 for maximum in-cylinder combustion pressure. Similarly, the RCCI method effectively decreases NOx and soot emissions by 24.40-43.74 and 31.28-52.57 under max loads. However, the emissions of carbon monoxide (CO) and hydrocarbons (HC) are more than those of biodiesel at all levels of usage. Nevertheless, increasing the gasoline injection duration from 3ms to 5ms (milli second) in RCCI mode results in a drop in Pmax, NHRR, BTE, as well as NOx and soot emissions. The primary reason for this is mostly due to the superior cooling properties of gasoline and the longer period of time it takes for ignition to occur. The process of multi-response optimization is carried out utilizing VIKOR, B15 + 2ms GF and it is determined that operating at 80 load is the most optimal condition. © 2025 Elsevier B.V., All rights reserved.