The present invention relates to a cosmetic or dermatological composition comprising, in a physiologically acceptable support: a) at least one merocyanine compound of formula (1) or (2) and b) at least one oily phase and c) at least one C1-C4 monoalkanol. The present invention also relates to a non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of at least one composition as defined above. The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the skin, of at least one composition as defined previously. The invention also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.