In the title complex, [PdCl₂(C₁₂H₂₂S₃)]·0.8CH₃CN, a potentially tridentate thio­ether ligand coordinates in a cis-bidentate manner to yield a square-planar environment for the Pd^II cation [mean deviation of the Pd from the Cl₂S₂ plane = 0.0406 (7) Å]. Each square-planar entity packs in an inverse face-to-face manner, giving pairs with plane-to-plane separations of 3.6225 (12) Å off-set by 1.1263 (19) Å, with a PdPd separation of 3.8551 (8) Å. A partial aceto­nitrile solvent mol­ecule is present. The occupancy of this mol­ecule was allowed to refine, and converged to 0.794 (10). The synthesis of the previously unreported 3,6,9-tri­thiabi­cyclo­[9.3.1]penta­decane ligand is also outlined.

The asymmetric unit of the title compound, [Pd(C₂₂H₂₆N₂O₂S₃)]₂·CH₃CN, contains two complex mol­ecules and a single uncoordinated lattice aceto­nitrile solvent mol­ecule. The Pd^II cations have a trans-N₂O₂ square-planar geometry and the superposition of the two crystallographically independent Pd^II complexes yields an overall r.m.s. deviation of 0.292 Å. The PdPd separation in the asymmetric unit is 3.3776 (3) Å, while the PdN₂O₂ plane–plane fold angle is 1.62 (7)°. A short inter­molecular SS contact between the central S atom of one complex and its inversion-related symmetry equivalent of 3.663 (2) Å is observed. Part of the ligand chain (S—C—C—S) in each complex mol­ecule is disordered over two orientations and refined occupancies that converged to 0.450 (10) and 0.550 (10) for the one complex mol­ecule, and 0.789 (9) and 0.211 (9) for the other.