Time-of-flight mass spectrometry and ion-mobility studies were used to probe the conformations of a tetrahedral oligo p-phenylene vinylene sample. The radical cation and sodiated parent species as well as one fragmented ion were analyzed using ion mobility. Extensive molecular mechanics modeling was used to understand the effects that secondary structure has on the observed cross sections from ion-mobility experiments. The major features in the ion-mobility spectra appear to be due to arm-arm interactions caused by cis defects near the tetrahedral core of these oligomers.