Abstract: Twisted intramolecular charge transfer ( TICT ) of p-N, N-dimethy-laminobenzaldehyde (DMABA) in β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTMAB) mixed media is monitored by its typical dual fluorescence.The ratio of the intensity of TICTfluorescence band (a band) to that of normal band (b band) decreases with introducing CTMABat CTMABconcentration lower than β-CDin the solution, with the concomitant red shift of a band and the decrease of total fluorescence intensity,and the trends are opposite when CTMABconcentration is higher than β-CDconcentration.It is concluded that CTMABand /β-CDform a 1:1 inclusion complex and a premicellar aggregate of CTMABis present in CTMAB-β-CDmixed system at the concentration of CTMABhigher than that of β-CD,whose formation would be induced by β-CD.

Key words: TICT, DMABA.Cyclodextrin-surfactant system, Cyclodextrin induced aggregation