The synthesis of 3-methyl-1,4-diphenyl-7-thioxo-4,6,8,9-tetrahydropyrazolo[5,4-b] pyrimidino[5,4-e]pyridine-5-one (6) was achieved by two different one-pot multi-component synthesis (one-pot three-component and one-pot four component synthesis). Mono and dialkylation of 6 under different conditions gave compounds 7-11. The hydrazine 12 produced from reaction of 9 with N₂H₄ was subjected to reactions with some aromatic aldehydes, ethyl acetoacetate, acetyl acetone, ethyl cyanoacetate and triethyl orthoformate to give 13-17, respectively. Compound 12 upon reaction with CS₂, nitrous acid, benzoin, chloroacetone and phenacyl bromide gave 18,20,21,22. Alkylation of 18 with ethyl iodide, ethyl chloroacetate and phenacyl bromide gave 19a-c. The antibacterial and antifungal activities of selected derivatives were evaluated.