Abstract: In this paper,it was demonstrated that the interaction of excited acenaphthene with 1,4-dicyanobenzene will lead to the formation of exciplex and triple exciplex. The latter will be formed at higher concentration of acenaphthene. In the case of polyacenaph-thylene,intramolecular excimer could be formed between nonadjacent chromophores. As a result of interaction of excited polyacenaphthylene and 1,4-dicyanobenzene,triple exciplex can be formed too. The mechanism of the formation of triple exciplex was proofed as exciplex→triple exciplex but not excimer→triple exciplex.