4-Fluoronitrobenzene is an organic compound with the formula FC6H4NO2.

It is one of three isomeric fluoronitrobenzenes.

[2] A yellow oil, it is prepared from 4-nitrochlorobenzene using the Halex process: 4-Fluoronitrobenzene can be hydrogenated to give 4-fluoroaniline,[3] which is a precursor to the fungicide fluoroimide [de] and parafluorofentanyl.

Owing to the presence of the electron withdrawing nitro group, the fluoride is a good leaving group in fluoronitrobenzenes.

Thus reaction with phenoxide gives the mononitrodiphenylether.