Isophthalaldehyde is an organic compound with the formula C6H4(CHO)2.

It is one of three isomers of benzene dicarbaldehyde, a reduced analog of phthalic acid.

One preparation entails the Sommelet reaction of α,α'-diamino-ortho-xylene.

[3] Like many benzaldehydes, isophthalaldehyde forms a variety of Schiff base derivatives.

Being bifunctional (having two formyl groups), isophthalaldehyde allows the formation of polymers or covalent organic frameworks upon reaction with di- or triamines.