This current investigation represents the new series of fused thieno‐pyrimidine with synthesized tetrazole analogs (6a–j). Intermediates thieno‐[2,3‐d]‐pyrimidine were prepared by utilizing the Gewald method, and tetrazole (5a–j) was synthesized by [3 + 2] cycloaddition of azide and appropriate nitrile. All the prepared novel molecules were characterized and confirmed by 1HNMR, 13CNMR, LC‐MS, and FT‐IR spectral analysis.