We have investigated the thermal and photochemical characteristics of silver 4-nitrobenzoate (Ag-4NBA) using various analytical tools, such as, X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. The XRD pattern was composed of a series of peaks that could be indexed to (0k0) reflections of a layered structure. Upon heating the sample, structural changes took place particularly at two specific temperatures. The binding state of the carboxylate group changed from bridging to unidentate at similar to380 K. A second dramatic structural change occurred at similar to590 K, producing 4NBA-capped Ag nanoparticles. The latter transition temperature for Ag-4NBA is about 80 K higher than that for silver alkanecarboxylates, and such enhanced thermal stability of Ag-4NBA must be associated with the conjugation of the carboxylate group to the aromatic ring. On the other hand, Ag-4NBA was readily subjected to photolysis even by visible radiation. Under irradiation by a He/Ne laser at 632.8 nm, 4-NBA-capped Ag nanoparticles were produced from Ag-4NBA. Upon irradiation by an Ar+ laser at 514.5 nm, nitro-to-amine group conversion took place consecutively, finally producing 4-aminobenzoate-capped Ag nanoparticles. Accordingly, the Raman spectrum of Ag-4NBA taken using the 514.5-nm line as the excitation source became identical to the surface-enhanced Raman scattering (SERS) spectrum of 4-NBA adsorbed on Ag.