The color reactions of cyclohexanone, and acetophenone, with 1, 3, 5-trinitrobenzene were investigated. Two main coloring matters, a Meisenheimer type compound, IV Na and a tricyclic type compound, V Na, were isolated from the reaction mixture of cyclohexanone. In the case of the reaction of acetophenone with excessive 1, 3, 5-trinitrobenzene, the Meisenheimer type compound, VII Na, was the sole coloring matter. From a comparison of the absorption spectral behavior of them with the color reaction mixtures, mechanisms of the color reactions of cyclohexanone, and acetophenone, under the spot test procedure were elucidated.