In recent years, improving the appropriateness of biofuel for CI engines through the use of fuel additives as low carbon alcohol has emerging as a potential area for research. The purpose is to enhance combustion efficiency, reduce greenhouse gas emissions, and improve fuel sustainability in compression ignition engines. The present experimental investigation focuses on the development of blends with ethanol, propanol and n-butanol with diesel and Prosopis Juliflora biodiesel using splash blending technique and examining their performance characteristics in CI engine. It was inferred that the DBP ternary blend exhibited better BSFC (0.3 kg/kW.h) and brake thermal efficiency (3.8 %) is closer to the diesel values. However, the CO and HC emissions are 34 % and 39.3 % lower than the diesel, respectively. Similarly, the peak pressure of the DBP blend has outperformed all other fuel blends. Considering the NOx emissions of DBP, there is a 2.63 % reduction among all the alcohol blends compared to diesel. Response Surface Methodology was adopted with Central composite design to identify the optimised blend and engine outcomes with a desirability level of 91.7 % by the outcomes. Based on the experimental and optimisation results, the DBP blend is an optimum blend for choosing a future alternative. © 2025 Elsevier B.V., All rights reserved.