The research included synthesis of 2-mercapto benzoxazole  (MBO) (1) ) from the reaction of ortho hydroxyl aniline with carbon disulfide in ethanolic potassium hydroxide. The hydrazine benzoxazole HMBA2 (2) was synthesized from the reaction of compound MBO (1) with hydrazine hydrate in presence of alcohol. Compounds (3(a- e)) were synthesized by condensate on of substituted Benzaldehydes with 2-Hydrazino benzoxazole HMBA2. The Ethyl2-(benzoxazolylthio) acetate EMBA1 (4) obtained from the reaction  of compound MBO (1) with solution of ethyl chloro acetate using KOH alcoholic .Finally the compound hydrazide HMBA(5 (a- e))  was synthesized from the reaction of compound (4) with hydrazine hydrate in presence of alcohol .All these synthesized compounds were characterized on the basis of their 1H-NMR ,IR, The study is Showed biological activity for chemical compounds, at three concentration 100, 200, 300 ppm in toxic potato Dextrose Agar (PDA) medium method against phytopathogenic fungi three species  Fusariumgraminarium, Sclerotiniasclerotium and Rhizoctoniasolani, its isolation on nutritious PDA medium from root plants wheat ,eggplant and cotton continually, diameter measure of fungi growth colony result showed all compound growth inhibition barring MMBA compound non effective inhibition its, appear MBO moral  superiority after bring HMBA2 both induce inhibition amount 49.69 and 34.22% continually. Compound concentration its  average effect result reveal third significant superior on first and second concentration, interference effect concentration and species chemical compound notice higher inhibition amount 100%with third concentration MBO compound all test its fungi .