A novel and convenient synthesis of substituted 6-(substituted thio) tetrazolo[1,5-a] triazolo[3,4-c] quinoxalines has been carried out. The newly synthesized compounds have been characterized by IR, 1HNMR, and mass spectral data followed by elemental analysis. All the newly synthesized heterocycles have been screened for their in vitro anti-microbial activity against Staphylococcus aureus and Bacillus subtilis as Gram-positive bacteria, Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria. They were also evaluated for their in vitro anti-fungal potential against Candida albicans. Few of them have exhibited the promising activity.