Department of Pure and Applied Chemistry. M. D. S. University, Ajmer-305 009, India Fax: 91-0145-787055 Manuscript received 9 January 2001, revised 7 June 2001, accepted 24 June 2001 2-Acctoacetamidobenzothiazoles (2), prepared by reacting substituted-2-aminobenzothiazoles and methylacetoacetate, are converted into benzothiazo-2-carboxamido-α,ß-unsaturated ketones (4) by condensation with different aromatic aldehydes (3). The ketones (4) on refluxing with phenylhydrazine produce the title compounds (5).