The invention relates to a composition comprising: i) at least one oxidation base, preferably of heterocyclic and/or para-phenylenediamine type and ii) at least one heteroaryl coupler of formula (I), with R1, R2, R3, A and X as defined in the description. The invention also relates to a process for dyeing keratin fibres using ingredients i) and ii) to a kit comprising ingredients i) and ii) and to the use of ingredient i) combined with ii) for dyeing keratin fibres. The composition of the invention leads to particularly powerful, chromatic and sparingly selective colourings.
