A series of some 2-pyrazolideno-1,3,4-Thiadiazoline Compounds [10-15] was prepared under conventional and thermal conditions using an active starting material thiocarbohydrazide  as a good precursor. Thiocarbohydrazide  was firstly prepared through direct addition reaction between (80%) hydrazine hydrate and carbon disulfide in aqueous media and reflux conditions, then it will be converted to itʼs hydrazone derivative via condensation reaction with benzophenone in acidic media at room temperature to afford compounds 1-(diphenyl methylene) thiocarbohydrazone , and the later one was underwent catalytic intracyclization reaction to give 2-hydrazinyl-5,5-diphenyl-2,5-dihydro-1,3,4-thiadiazoline compound  in presence of ferric chloride as a selective catalyst . Finally compound  reacted with freshly prepared chalcones (using diffrent substituted benzaldehyde and two types of ketones represented by acetophenone and m-methoxy acetophenono) [4-9] via traditional method to yield the titled compound represented by 1-(5,5-diphenyl-2,5-dihydro-1,3,4-thiadiazol-2yl)-3,5-diaryl-4,5-dihydro pyrazolidine compounds [10-15]. All prepared compounds were illustrated by the available physical and spectral data represented by U.V, FT-IR, H1-NMR & C13-NMR.
Thiocarbohydrazide, Pyrazolidines, 1, 3, 4-thiadiazolines, Hydrazones