Monolayers of N,N-ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C13) deposited on flat, vicinal, and alkane thiol-terminated surfaces of Au(111) exhibit a number of different phases. By carefully analyzing the structure of each monolayer phase, the authors are able to elucidate the effects of natural templating, provided by Au surface reconstruction and by the geometric constrain of stepped Au surface, in determining the phase of the PTCDI-C13 monolayer. This highlights the utility of surface templating for supramolecular chemistry and molecular electronics. (C) 2010 American Vacuum Society. [DOT: 10.1116/1.3462036]