Diethylaniline is the organic compound with the molecular formula (C2H5)2NC6H5.

It is a colorless liquid but commercial samples are often yellow.

With formylbenzenedisulfonic acid it condenses to give Patent blue VE, and with hydroxybenzaldehyde followed by sulfonation one obtains Patent blue V. When treated with phosgene, one obtains Ethyl violet, an analogue of methyl violet.

[3] In organic synthesis, the complex diethylaniline·borane (DEANB) is used as a reducing agent.

[5] Diethylaniline may be genotoxic because it has been found to increase the rate of sister chromatid exchange.