Calotropis procera and Nerium indicum were evaluated as potential renewable sources of energy and chemicals. The different plant parts-leaf, stem, bark and the plant as a whole were analysed separately for alpha -cellulose, lignin, ash and elemental compositions. alpha -cellulose in the whole plant portion were 56.42 % and 57.35 % for C procera and N indicum, while lignins were 20.42 % and 23.25 % respectively. The elemental composition of C, H and N in the plant were 40.36, 6.19 and 2.06 % for C procera, while for N indicum, the C, H and N were 38.54, 5.86 and 1.82 % respectively. Of the two species, C procera contained 4.71 % oil, 11.45 % polyphenol, 3.46 % hydrocarbon, 7.20 % protein and 22.8 % unsaponifiable matter, while N indicum was found to contain 4.36 % oil, 8.62 % polyphenol, 2.18 % hydrocarbon, 7.55 % protein and 49.8 % unsaponifiable matters. The calorific values of the plant species were also determined and found to be 17.5 MJ/kG and 15.3 MJ/kG for C procera and N indicum respectively. Therefore, the species may be considered far large scale cultivation as an alternative source for producing hydrocarbon and chemical feedstocks.