Collision cross-sections of gas-phase (CsI)(n) = 1-7CS+ cluster ions formed by pulsed-UV laser (355 nm) desorption ionization are measured by ion mobility-mass spectrometry. Experimental collision cross-sections are compared with calculated cross sections of candidate structures generated from a search for the lowest energy structures at the DFT/B3LYP/LACV3P** and MP2/LACVP3P** levels. The relative stabilities of these candidate structures are examined by IM-CID-MS, and the experimental results are compared to theoretical predictions. Analysis of (CsI)(n) = 1-7CS+ Cluster ion dissociation energies shows that the lower fragmentation thresholds are observed for cluster ions with the lower predicted stability.