Use of diluting agents in neat vegetable oil to reduce its density and viscosity, is arguably the best alternative route for vegetable oil usage in diesel engines. It is suitable where the complex transesterification process for biodiesel production is not feasible. In this study, Calophyllum vegetable oil was diluted with 10%, 20% and 30% by volume of Isopropyl alcohol and named as CI10, CI20 and CI30 respectively. Neat diesel was termed as D100. An exhaustive field trial on a single cylinder agricultural diesel engine indicated that full load brake thermal efficiency of D100 was 26.4% followed by CI10, CI20 and CI30 test fuels. Emissions of carbon monoxide, hydrocarbons and smoke were impressively reduced by a margin of 17-63% for the isopropyl alcohol containing test fuels as compared to the diesel baseline. However, oxides of nitrogen emissions were marginally higher for the isopropyl alcohol blends. The average peak in-cylinder pressure over 91consecutive cycles exhibited by D100, CI10, CI20 and CI30 were 66.5, 66.2, 62.9 and 62.7 bars respectively indicating decrease in peak pressure with increase in volume fraction of isopropyl alcohol in the test fuel. However, all the test fuels indicated lower peak pressure than the baseline data of diesel. Ignition delay was found to increase marginally with increase in isopropyl alcohol composition in the test fuels. Full load cumulative heat release exhibited by D100, CI10, CI20 and CI30 were 1033.58, 1005.15, 972.12 and 957.63 Joules respectively.