A powder of a selective reducing agent, sodium triacetoxyborohydride (Na(OAc)(3)BH4), has been attached to an atomic force microscopy tip and used to selectively reduce a monolayer of imines (formed from the reaction of cystamine molecules with cyclopentanone) to their corresponding secondary amines within a well-defined region. Confirmation of the completion of the reaction came through the use of surface mid-IR results as well as with the use of the chloranil test in which the secondary amines were reacted with acetaldehyde to form an enamine that was then conjugated with chloranil to form a localized colored complex, observable by optical means, in a spatially distinct area, traced out by the scanning tip.