Using common substitution reactions, several 4-phenyl-delta2-1,2,4-triazoline-5-thione [I] and 4-phenyl-3-(pyridin-3-yl)-delta2-1,2,4-triazoline-5-thione [II] derivatives of 1-substituted-3-R-4-phenyl-delta2-1,2,4-triazoline-5-thione were obtained. These new compounds were screened for their antibacterial activities.