This contribution reports on the anion exchange characteristics of self-assembled monolayers composed of high-beta stilbazolium chloride moieties as assessed by X-ray photoelectron spectroscopy, optical spectroscopy, and polarized second harmonic generation (SHG) spectroscopy. At moderate chromophore surface coverages (approximately 1 X 10(14) molecules/cm2) in acetonitrile or methanol, replacement of approximately 60% of the Cl- counterions by I-, p-aminobenzenesulfonate, or 4-[4-[(diethylamino)phenyl]azo]benzenesulfonate (ethyl orange) is observed. However, negligible exchange is detected at higher chromophore surface coverages (greater-than-or-equal-to 2 X 10(14) molecules/cm2) or when the monolayer is functionalized with a siloxane overlayer. Polarized SHG measurements at 1064 nm reveal ion exchange-induced increases in chi(zzz)(2) of 34%, 25%, and 44% for I-, p-aminobenzenesulfonate, and ethyl orange, respectively. However, changes in the average chromophore orientation angle with respect to the surface normal are less-than-or-equal-to 2-degrees, implicating changes in anion-cation pairing as the source of the large enhancements in chi(zzz)(2).