A thermal dye transfer assemblage comprising:(a) a dye-donor element comprising a support having thereon a dye layer comprising a dye dispersed in a polymeric binder, the dye comprising an N-arylimido-ethylidene-benz[c,d]indole dye precursor, and(b) a dye-receiving element comprising a support having thereon a polymeric dye image-receiving layer, the dye-receiving element being in a superposed relationship with the dye-donor element so that the dye layer is in contact with the dye image-receiving layer, the dye image-receiving layer containing an organic acid which is capable of converting the dye precursor into a cationic magenta anilinovinyl-benz[c,d]indolium dye.