The instability of biodiesel fuels during storage is a key issue. In this work, biodiesel has derived from Phoenix dactylifera L (Date seed) is doped with CLP in various concentrations from 500 ppm to 2000 ppm to improve storage stability. Doping the samples with coffea leaf pigment made them more stable than plain biodiesel fuel. Using 2000 ppm of CLP in the DS (B20), engine testing proves that the addition of antioxidants improves engine performance to a considerable extent. The performance, combustion, and emission experiments were performed on the DICI engine by fueling with DS doped with CLP antioxidant additives. Brake thermal efficiency was found to increase for all test blends with respect to load due to the increased power output at higher loading conditions. However, the biodiesel with antioxidant-doped blends depicted a declining trend in brake thermal efficiency at all loading conditions. The biodiesel blend doped with antioxidant additives reduces the degree of oxidation of fuel molecules thereby restricting the combustion temperature where reduces the BTE. On analyzing the emission characteristics, the antioxidant addition diminishes the free radical sites and kerbs the oxidation reaction thereby augmenting CO and HC emissions. Emission of HC augmented on adding of CLP concentration in biodiesel due to the retarded oxidation of the hydrocarbon chain as a result of antioxidant addition. On the other hand, a reduction in combustion temperature leads to a reduction of NOX emissions for all the antioxidant-doped blends as oxidation of nitrogen is curbed by restricting the free radical sites and quenching the combustion temperature.