Fluorescence excitation spectra and fluorescence lifetimes at specific wavelengths are reported for anthracene and anthracene-argon complexes in a supersonic jet. At low argon pressures, complexes are observed with lifetimes and transition energies which are not dependent on the argon pressure. At high pressures, the lifetimes reach a limiting value while the wavelength maximum continues to red shift within the pressure range observed. The possible relationship to solvent or matrix effects on a central ion are discussed.