An efficient synthesis of novel spiro(imidazo[4′,5′:4,5′]benzo[1,2-e][1, 4]thiazepine)-9,3′-indolines has been accomplished from 5-amino-2-mercapto benzimidazole, istains and mercapto acetic acid. Compounds 6 were characterized by IR, 1H NMR, 13C NMR and mass spectral data. The title compounds 6a–6e were evaluated for their antimicrobial, anti-inflammatory and antioxidant activity. Compounds 6a–6e exhibited significant antimicrobial activity, and as potent anti-inflammatory and antioxidant activities as that shown by standard drugs.