The replacement of self-assembled monolayers of Di(phenylethynyl)benzenethiol (1) on a Au( 1 1 1) surface by immersion in n-alkanethiols solutions is followed ex situ using scanning tunneling microscopy (STM), Over the first hours, the replacement appears to start at the domain boundaries of the original monlayers, leaving initially elevated islands of 1 over the background (0.7 nm STM height difference for decanethiol), It then proceeds more slowly, reducing the islands until most disappear but at very long times, some isolated and tip-resolution-limited protrusions remain.