In this experimental work focused on, the performance, emission, and combustion characteristics of Nano methyl esters of Punnai oil and Waste Cooking oil, and their diesel blends in a Compressed Ignition were experimentally tested. In the study, Nano Punnai oil methyl esters (NPOME), and Nano Waste Cooking Oil Methyl Esters (NWCOME) were prepared by the transesterification process. The Bio diesel-diesel blends were prepared by mixing 10%, 30%, 50%, and 70% of biodiesel with diesel. The effects of two nano methyl esters and their diesel blends on engine performance, combustion, and exhaust emissions are tested at different engine loads. Experimental results concluded that up to 30% of no methyl esters did not affect the performance, combustion, and emissions characteristics. On the other hand, above B30 (30% Biodiesel with 70% diesel) a reduction in performance, combustion, and emission characteristics is clear from the study.