Pyridine-4-carbaldehyde is an organic compound with the formula C5H4NCHO.

Pyridine-4-carboxaldehyde is a colorless liquid, although aged samples can appear yellow or even brown.

It undergoes many reactions expected for aromatic aldehydes such as reductive amination and Schiff base formation.

[1] It condenses with pyrrole to give tetrapyridylporphyrin.

[2] The pKa has been experimentally determined by NMR spectroscopy to be 4.72.