A carbosilane dendrimer terminated with 4-pyridinealdoxime (G4-48PyA) was synthesized and its monolayer properties on aq. aluminum subphase were examined. G4-48PyA was not totally spread to monolayer and the surface pressure-area isotherms were dependent on the subphase ion and pH. The aggregated images of the monolayers were monitored by Brewster angle microscopy and those structures were also confirmed in the LB film by atomic force microscopy. The UV spectra showed that the pyridinealdoxime moiety was hydrolyzed from the dendrimer upon spreading on water subphase. The incorporation of the aluminum ions into the LB film was found by X-ray photoelectron spectroscopy.