Insect pests infest and damage agricultural stored grains and processed food products both qualitatively and quantity since time long before. Several synthetic chemical have been developed and applied as insecticides to manage these losses, but, extensive uses of these on this strategy have created serious environmental and health issues. To mitigate these problems, several natural volatile organic chemicals have been explored since last three decades and received significant results. In this continuation, two volatile organic chemicals, carvacrol and menthone have been evaluated for repellent, toxic, oviposition, developmental and feeding inhibitory activities against wheat flour insect, Tribolium castaneum (Coleoptera: Tenebrionidae). These two volatile organic chemicals repelled the adults of T. castaneum in filter paper repellency assay and cause acute toxicity in larvae and adults of T. castaneum in fumigant and contact toxicity assays. These two organic chemicals reduce oviposition and interfere with the transformation of larva to pupa and pupa to adult. Besides, deterrence in feeding habit of adults has also been recorded. These two chemicals inhibit acetylcholine esterase activity in adult insects suggesting probable neurotoxic mode of action in insects. These outcomes of the study suggest carvacrol and menthone as the key components in eco-friendly insecticide formulation based on volatile organic chemicals