4-Nitrobenzoic acid is an organic compound with the formula C6H4(NO2)CO2H.

It is a pale yellow solid.

It is a precursor to 4-nitrobenzoyl chloride, the precursor to the anesthetic procaine and folic acid.

[7] Alternatively, it has been prepared by nitration of polystyrene followed by oxidation of the alkyl substituent.

This method proceeds with improved para/ortho selectivity owing to the steric protection of the ortho positions by the polymer backbone.