A novel friction-sensitive fluoresence probe based on intramolecular exciplex formation, (9-anthrylmethyloxymethyl)pyrene (AMOP), was used to study the micellization of amphiphilic molecules such as sodium dodecyl sulfate (SDS) and hydrocarbon-modified polyethylene glycol (HM-PEG) in water. Results demonstrate that AMOP can serve as a sensitive probe for micellization of both SDS and HM-PEG. In addition, AMOP reveals information about the microviscosity of SDS and HM-PEG micelles, which is in good agreement with the results obtained from other fluorescence probes based on intramolecular excimer such as dipyrenylpropane (Py(CH2)(3)Py) and bis(1-pyrenylmethyl) ether (dipyme, PyCH2OCH2Py).