The alkylation of 4-cyano-5, 6-dimethylpyridazin-3 (2H)-thione 3 with some halo compounds gave the S-alkylated products 4a–c, which upon treatment with ethanolic sodium ethoxide afforded the cyclized thienopyridazines 5a–c as products. Pyridazothienotriazines 6a–c