The adsorption of 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) on a gold surface has been studied using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) under ultrahigh vacuum conditions. TTTA was deposited onto the gold substrate by gas-phase dosing. XPS and UPS spectra show that TTTA molecules strongly adsorb on the gold surface. In addition, the UPS spectrum of the TTTA monolayer is in good agreement with the gas-phase UPS spectrum of TTTA, which indicates that the molecules adsorb as a radical without electron transfer from the gold substrate. (C) 2007 Elsevier B.V. All rights reserved.