10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 2 2011 (April - June) As a part of systematic investigation for synthesis, characterization and biological activity of several new substituted tricyclic compounds: 7-(phenylsulfonyl)-N-(phenyl)-5,6,7,8-tetrahydropyrido[4',3':4,5]-thieno[2,3-d]pyrimidin-4-amine (7a-7t) have been synthesized from 7-(phenylsulfonyl)-4-(chloro)-5,6,7,8-tetrahydropyrido[4',3':4,5]-thieno[2,3-d]pyrimidine (6a-6e) using piperidin-4-one Hydrochloride and benzenesulfonyl chloride as the starting material. All the synthesized products were evaluated for their antibacterial activity against lessThan i greaterThan Bacillus substilis, Escherichia coli. Klebsiella pneumoniae lessThan /i greaterThan and lessThan i greaterThan Streptococcus aureus lessThan /i greaterThan bacteria and antifungal activity against lessThan i greaterThan Aspergillus niger, Aspergillus flavus, Fusarium oxisporium lessThan /i greaterThan and lessThan i greaterThan Trichoderma viride lessThan /i greaterThan fungi respectively. Most of the synthesized compounds exhibited significant anti-bacterial and anti-fungal activities. The structures of all the synthesized compounds have been determined by their spectral and microanalytical data. Manish Mittal, Suraj M. Sarode And Dr. G. Vidyasagar Pyridothiophene, Pyridothienopyrimidines, Sulphonamides, Antibacterial activity 188-196