Process for the preparation of a compound of Formula (I): the process comprising the reaction of a compound of Formula (II) with malononitrile in the presence of a base and a palladium catalyst, wherein X, Y and Z, independently of each other, represent fluoro, chloro or C1-4alkyl; and L is a leaving group; with the proviso that 1 or 2 of X and Y are, independently of each other, fluoro or chloro.