The fluorescent probe technique was applied to study intefacial microenvironmental states between a silica surface and solvents on account of its high sensitivity. Dicyanoanthracene (DCA) was employed as a fluorophore because of the sensitivity to solvent polarity and of the ability to form an exciplex with phenanthrene. DCA was bound on a quartz plate covalently through silylation. Fluorescence of DCA on the surface displayed a marked red shift when the plate was immersed in nonpolar aliphatic hydrocarbon solvents, showing that the fluorophore is located in a rather highly polar environment owing to residual silanol groups and possibly to adsorbed water molecules on the surface. This was supported by the fact that the red shift was reduced by capping silanol groups with trimethylsilyl chloride. Immersion of a DCA-modified quartz plate in a hexane solution of phenanthrene resulted in the emergence of a fluorescence at red-shifted wavelengths due to an exciplex between DCA and phenanthrene at the interface. The fluorescence maximum of the exciplex was also sensitive to the micropolarity on the surface. The significance of the exciplex fluorescent probe has been discussed.