Real-time conductance switching and place-exchange up and down substrate step edges have been measured for oligo(phenylene ethynylene) (OPE) molecules inserted into host dodecanethiolate self-assembled monolayers (SAM). These measurements were obtained by placing a scanning tunneling microscopy tip over individual nitro-functionalized OPE molecules and recording apparent height versus time. In addition, real-time measurements for the host SAM were acquired and indicated small motions for the monolayer−substrate system.