The subterranean termites Odontotermes obesus and Heterotermes indicola are highly infesting wood pests that cause economic losses that cost billions of dollars throughout the world – especially in tropical and subtropical regions. It is highly significant to formulate insecticides from plant-based chemicals rather than synthetic ones. The eight plant species resistant to termites were selected for screening as anti-termite phytochemicals. Extracts from different parts of the plants were collected by using ethanol solvents in different ratios. These extracts were evaluated for their toxicity against termites and their gut flagellates at subsequent concentrations in the range of 100-2000 ppm to find LC₅₀. Although the plants tested were found to be effective, extract from Grevillea robusta showed maximum mortality and reduced termite survival rate to 94% (LC₅₀ = 1391.01) and 90% (LC₅₀ = 1607.95) of O. obesus and H. indicola respectively. This extract also reduced the survival rate of hindgut flagellates of H. indicola up to 95% with an LC₅₀ value of 502.64 ppm. The extract of Grevillea robusta was characterized by UV-Vis spectroscopy, FTIR and GC-MS analysis. Two absorption peaks were recorded by UV-Vis spectroscopy at 208.94 and 282.97nm having absorption of 2.33 and 0.811 respectively. FTIR analysis confirmed the presence of amines, alcohols, alkanes, nitriles, aldehydes, ether and halo compounds. GC-MS analysis revealed the presence of 15 phytochemicals with a high percentage of Coumarin (30.64%), 7-hydroxy, Methyl hexofuranoside (27.63%) and 9,12,15-Octadecatrienoic acid (Z,Z,Z) (8.97%). The natural phytochemicals from G. robusta having termiticidal and protozocidal potential being eco-friendly can replace synthetic pesticides for termite control.