Pyrimidine derivative (1) is prepared through the reaction of 4-oxo-4-biphenylbut-2-enoic acid and thiourea.  Reaction of 1 with ethyl chloroacetate afforded the corresponding pyri-midine ester (II) which is converted to the arylidenes (III & IV) and hydrazine derivative (V). The behaviour of the obtained hydrazine was studied towards sodium nitrite/HCl, 3.4.5-trimethoxybenzaldehyde and acetone. Reaction of pyrimidine derivative 1 with acetyl chloride gave the N-acetyl derivative (X), which is converted to the pyrimidine-pyridone derivative (XI). The enol form of the pyridone ring is used in the preparation of the chloro derivative (XII). The reaction of the chloro derivative with sodium azide, amines, hydrazine hydrate and benzenesulfanilamide derivatives have also been taken into consideration. The in-vitro anti-bacterial screening revealed that some of the new compounds possess activity against Gram-positive, Gram-negative bacteria and fungi.