Gas-phase ion-molecule association reactions of n-propyl sulfide radical cation ([n-Pr2S](+)) with n-propyl sulfide (n-Pr2S) were studied by equilibrium methods in CO2 bath gas to investigate the bond energy of the 2c-3e bond. The 2c-3e S therefore S bond enthalpy in [n-Pr2S therefore Sn-Pr-2](+) was determined to be 119 kJ/mol at 507 K. This results in a scaled S therefore S bond energy of 123 kJ/mol. The S therefore S bond enthalpy in the i-propyl sulfide dimer cation ([i-Pr2S therefore Si-Pr-2](+)) could not be determined due to a fragmentation reaction, the loss of an i-propyl group. MS/MS metastable and collision-induced dissociation experiments were carried out to determine metastable fragmentation pathways and to aid in structure analysis. The results are consistent with association products containing 2c-3e bonds; statistical unimolecular metastable fragmentation of the association adduct, [i-Pr2S therefore Si-Pr-2](+), confirms the loss of the i-propyl group, which prevented the equilibrium experiments.