Abstract: The present invention relates to compounds shown in the general formula (I) or (III), the salts thereof or their mixtures, as well as their preparation method and application. In the general formula (I), X1 is H or CO2H; X2 is OH or phenyl group with 0-2 sulfonic acid substituents, and the sulfonic acid substituents are located at random positions of a benzene ring; when X2 is OH, X1 is H; when X2 is phenyl group with 0-2 sulfonic acid substituents, X1 is H or CO2H; n is an integer of 0-2; and in the general formula (III), n and m are respectively an integer of 0-2. The compounds and the mixtures not only have improved light resistance, ozone resistance and water resistance, but also have excellent water solubility and long-term stability in ink-jet ink.