Isothiobiurets and its derivative are found to be having physiological and potential chemotherapeutic properties. In view of this certain 1-hepta-O-benzoyl-β-D-lactosyl-5-substituted-2-Sbenzyl- 2-isothiobiurets have been synthesized for the first time by the interaction of 1-hepta-O-benzoyl-β- D-lactosyl-2-S-benzyl isothio-carbamide with various isocyanates. The structures of these new 2- isothiobiurets have been established on the basis of usual chemical transformations and IR, NMR and Mass spectral analysis. The polarimetric study of title compounds has been carried out. All the compounds are screened for their antibacterial and antifungal activity.