Two exciplex systems, anthracene-N,N-dimethylaniline and anthracene-julolidine, were studied. Although both N,N-dimethylaniline (DMA) and julolidine are aniline derivatives, they differ with regard to the twisting motion of the amino group. A comparative study of the effects of the donor concentration, medium polarity, temperature and magnetic field on the luminescence of the two exciplexes was performed. Differences in the behaviour of the two exciplexes were ascribed to differences in the structures of the two donors.