Upgraded bio-oil derived from the thermochemical conversion of biomass has the potential to replace liquid fossil fuels. In this work we report the generation of high energy density oil via the slow fixed-bed pyrolysis of Jatropha curcas shells and the subsequent upgradation of the crude bio-oil by means of a simple organic reaction. The optimization for maximum productivity of the bio-oil was carried out at temperatures of 300, 400, 500, and 600 degrees C. Kinetic study indicated the favorable heating rate to be 5 degrees C min(-1). The maximum bio-oil, with a yield of 31.14%, was obtained at 400 degrees C with a holding time of 4 h. The bio-oil, containing ca. 40% carbonyl (>C=O) derivatives, was converted into the corresponding methylene (-CH2-) derivative by treatment with hydrazine hydrate/sodium hydroxide. The resultant oil, containing mostly ethylbenzene, had a high calorific value and thus might be suitable to replace fossil diesel or gasoline. The bio-chars obtained at the specific carbonization temperatures were also characterized for their potential use as a solid fuel.