The present invention relates to an improved and efficient process for the synthesis of 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione, compound of formula (I) (Prothioconazole). The present invention more particularly relates to an improved process for manufacturing of 2-(1-chloro-cycloprop-1-yl)-3-(2-chloro phenyl)-2-hydroxy propyl-1-hydrazine (compound of formula III) and 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazolidine-3-thione (compound of formula II) which are mainly used for synthesis of Prothioconazole which is knows as an active compound with microbicidal fungicidal properties.