Quinonedichlorodiimide (I) reacts with aromatic secondary and tertiary amines to yield green colored compounds. The chemical structure of these colored compounds is investigated from the spectral data (infrared, ultraviolet, nuclear magnetic resonance, mass) and the chemical reactions. The color of the reaction product of I and N-ethyl-m-toluidine (II) or N, N-diethyl-m-toluidine (III) is changed mutually between green and violet by oxidation and reduction. These results and the spectral data suggest that these reactions are electrophilic displacement reactions in the ortho or para position of the alkylamino group and I reacts with II or III at the rate of 1 : 2.