Three compounds of benzothiazole were synthetized as active ingredient and prepared as 10 % suspensions concentrate (SC). They were evaluated against the second and fourth instar larvae of the cotton leafworm S. littoralis (Boisd.), under laboratory conditions. LC₅₀ values showed that formulation (1) gave the highest toxic effect against 2^nd and 4^th instar larvae after 48 hrs from treatment and gave the best effect as antifeedant followed by formulation (3) and formulation (2). Semi field experiment was done to evaluate the initial and latent effects of the formulated compounds compared with commercial insecticide chlorpyrifos 48% EC (Dursban), the results showed that formulation (1) gave 100 % prevention of adult emergency due to the high initial and latent effects and lowest pupation percentage as the same as chlorpyrifos followed by formulation (3) and formulation (2) with the 2^nd and the 4^th instar larvae. Whereas Formulation (1) at 1 % is already as the same of recommended insecticide chlorpyrifos, therefore it could be recommended to use the new formulations as alternative of hazard conventional insecticides in controlling cotton leafworm in different crops after conducting the other necessary open field experiments.