A series of N-lactosides like 1-hepta-O-benzoyl--D-lactosyl-3-aryl thiocarbamides, thiocarbamates and benzothiazolyl thiocarbamides were synthesized by the interaction of 1-hepta-Obenzoyl- -D-lactosyl isothiocyanate with aryl amines, alcohols and 2-amino benzothiazole / substituted benzothiazoles, respectively. 1-Aryl-5-hepta-O-benzoyl--D-lactosyl-2-S-benzyl-2, 4-isoditiobiurets were synthesized by the interaction of 1-hepta-O-benzoyl--D-lactosyl isothiocyanate with S-benzyl-aryl isothiocarbamides. 3 – Hepta – O - benzoyl – 6 - D - lactosylimino - 5- arylimino - 1, 2, 4 - dithiazolidines (hydrobromide) were synthesized by oxidative debenzylation and cyclization of 1-aryl-5- hepta-O-benzoyl--D-lactosyl-2-S-benzyl-2, 4-isodithiobiurets with molecular bromine in chloroform medium. These newly synthesized compounds were characterized on the basis of usual chemical transformations, IR, NMR and mass spectral analysis. In the present investigation, activities of these Nlactosides against pathogenic baceteria and fungi such as E. Coli, S. aureus, P. vulgaris, S. typhi, Candida guilliermondii and A. niger are discussed.