The　molecule　of　nile　red　(NR)　contains　a　big　aromatic　ring　and　a　carbonyl　oxygen　(electron　acceptor)　that　can　hydrogen-bond　with　a　water　molecule,　resulting　in　high　sensitivity　to　the　microenvironments　of　the　micellar　palisade　layer　in　which　NR　is　solubilized.　In　the　aqueous　micellar　solution　of　dodecyltrimethylammonium　bromide　(C(12)TABr),　the　dual　fluorescence　of　NR　appeared　and　the　maximum　emission　wave　lengths　were　at　578　and　630　nm,　respectively.　The　dissociation　degree　of　the　counterion　from　sodium　dodecyl　sulfate　(SDS)　micelle　was　found　to　be　larger　than　that　of　C(12)TABr.　This　increased　both　the　microenvironment　polarity　around　NR　and　the　hydrated　water　for　the　heads　resulting　in　the　enhancement　of　the.　hydrogen　bonds　with　water.　As　a　result,　the　fluorescent　intensity　of　SDS　solution　was　reduced　compared　with　that　of　C(12)TABr　but　the　TICT　state　was　effectively　promoted　to　form,　which　produced　the　high　population　of　the　TICT　state　over　98%　and　thus　apparent　single　fluorescent　peak　at　634　nm.　By　the　high　sensitivity　of　NR　to　microenvironment,　the　information　about　uncompleted　structure　of　the　micelles　formed　initially　was　also　obtained,　which　indicates　that　NR　can　be　used　as　the　probe　to　determine　the　aggregates　formed　by　the　amphiphilies　with　strong　intermolecular　synergism.