The deep ultraviolet (lambda < similar to 250 nm) photochemistry of chemisorbed organosilane self-assembled films of the type R(CH2)(n)SiO-surface where n = 0, 1, 2 and R = phenyl, naphthyl, or anthracenyl is explored. Photochemistry is examined using 193 and 248 nm laser irradiation as well as deep ultraviolet lamp sources. It is demonstrated for a variety of systems, including single and multiple rings as well as heterocycles, that the primary photochemical mechanism is cleavage of the Si-C bond. Photocleavage of the organic group generates a polar, wettable silanol surface that is amenable to subsequent remodification by organosilane chemisorption, allowing the fabrication of high-resolution patterns of chemical functional groups in a single molecular plane. The use of patterned monolayers as templates of reactivity for subsequent selective chemical reactions is demonstrated.