Isoniazide can be synthesized by the known literature method. Nicotin-4-carboxylic acid (1) was converted into methyl ester by using methanol in presence of catalytic amount of sulphuric acid. The methyl nicotin-4-carboxylate (2) is converted into isoniazide (3) by the condensation with hydrazine hydrate in DMF. The isoniazide is then condensed with various aldehydes (4a-d) in absolute alcohol in presence of catalytic amount of acetic acid and final product N[(1E)- alkylidene]pyridine-4-carbohydrazide (5a-d) is subjected for further fluorescence study.