Synthesis of new bis-N-imino triazole derivatives containing oxadiazole 2, its Mannich base 3, and the S-alkyl group 4 is presented. Bis-N-iminotriazole 2 is formed in the reaction of compound 1 with terephthalaldehyde. Bis N-iminotriazole derivatives containing Mannich base 3 are synthesized by the reaction of morpholine or piperidine with the compound 2. The compound 2 also reacts with alkyl halides (butyl, pentyl, hexyl, heptyl) to give S-alkylated bis-N-imino triazoles 4. Structures of the new compounds are characterized by IR, H-1, and C-13 NMR, and mass spectral data. Antioxidant (FRAP and DPPH assay) and antileishmanial activities tests of the compounds indicate that the products 2, 3a, and 3b demonstrate moderate antioxidant activity in both DPPH and FRAP assays. The antileishmanial tests indicate high activity of the compounds 3a and 3b.