Exciplex fluorescence between N,N-dimethylaniline (DMA) and 1,4,6-trimethylnaphthalene (1,4,6-TMN) in isooctane was studied at room and elevated temperatures. This new exciplex, resulting from the association of the DMA donor to the TMN acceptor, was characterized by steady-state and time-resolved emission fluorescence spectroscopy. Temperature-de pendent measurements of the exciplex fluorescence reveal that the quenching mechanism leading to exciplex formation is sufficiently favorable to permit the exciplex to exist at temperatures approaching 150 degrees C. These results presage the utility of the DMA-TMN system as a new and viable diagnostic for the visualization of the gas/liquid distribution in flows.