The present invention relates to dissymmetric azomethine direct dyes of formula (I) and the leuco forms thereof of formula (II), and also to the use thereof for dyeing keratin fibres, in particular human keratin fibres such as the hair:in which formula (I) or (II) R1, R2, R3, R4, R5, R6, n and n′； are as defined in the description.The compounds of formula (I) or (II) according to the invention can give powerful, chromatic and sparingly selective colourings with good colour build-up, which are resistant to the various attacking factors to which keratin fibres may be subjected, such as inclement weather, light, washing and perspiration.
