[image omitted] Some new S-alkyl derivatives of indeno[1',2':4,5]thieno[2,3-d]pyrimidine 2-8 were prepared starting with pyrimidine-2(1H)-thione derivative (1). Also, treatment of compound 1 with 2,3,4,6-tetra-O-acetyl--D-glucopyranosyl bromide or 1-O-acetyl-2,3,5-tri-O-benzoyl--D-ribofuranose afforded nucleosides 9 and 12, respectively. Furthermore, deprotection of the latter blocked nucleosides was achieved in methanolic ammonia to afford the desired free S-nucleoside derivatives 10 and 13, respectively. Some prepared products were screened for antimicrobial activity, and some of them showed promising activity.