A new and facile synthetic route is proposed for the synthesis of some novel phenothiazines (5a-5g) based on the reaction of 2-amino substituted benzenethiols with p-tert-butyl phenol in good yield. The newly synthesized compounds were characterized by IR, H-1 NMR and mass spectral studies. Their antimicrobial activities against three strains of bacteria: Bacillus subtilis, Bacillus megaterium, Escherichia coli, and two strains of fungi: Aspergillus niger and Aspergillus oryzae, were investigated.