This book has been carried out to investigate the synthesis of 2-hydrazinothienopyrimidinone and 4-hydrazinothienopyrimidine and their reactions with some aliphatic carboxylic acids to produce triazolo compounds. Also, their reactions with carbon di-sulphid to produce mercapto triazolo compounds. Their reactions with nitrous acid to produce tetrazolo derivatives. Also, their reactions with haloketones, some aromatic aldehydes, some aromatic amines and other organic reagents to produce triazines and hydrazones derivatives which have biological activities. Also reaction of 2-hydrazinothienopyrimidinone with some aldo-sugars to produce acyclic-C-nucleosides which have biological activities.