Salicylaldehyde azine is used in the preparation of 2-oxo-2H-1-benzopyran-3-carboxylic acid 2-(2-oxo-2H-1-benzopyran-3-carbonyl)hydrazide by reacting with propadienedione . It has anthelmintic activity.

Salicylaldehyde is converted to chelating ligands by condensation with amines. With ethylenediamine, it condenses to give the ligand salen. Hydroxylamine gives salicylaldoxime. Condensation with diethyl malonate gives 3-carbethoxycoumarin (a derivative of coumarin) by an aldol condensation.

Salicylic acid can be synthesized from salicylaldehyde using KMnO4 without oxidising the hydroxy group (−OH). The hydroxy group that attached to the benzene isn't oxidized, because the C atom that bonded with the hydroxy has already use 2 electrons for sigma bonding and 1 electron for pi bonding.

SALICYLDEHYDE AZINE