Well-defined and homogeneous, contamination-free self-assembled monolayers (SAMs) were fabricated by the chemisorption of lip-NH-p-C6H4-N=N-p-C6H4-COOH (lip = alpha-lipoyl) onto gold. This adsorbate species is composed of a 1,2-dithiolane-based headgroup, an azobenzene-based (and hence photochromic) spacer unit and a carboxylic acid functional group. The SAM constituents are covalently attached to the substrate by the bidentate thiolate anchor groups and exhibit a strongly tilted binding configuration. (C) 2009 Elsevier B. V. All rights reserved.