Dimeric complexes of composition [Re₂X₂(CO)₆(HL)₂] were obtained by reaction of fac-[ReX(CO)₃(CH₃CN)₂] (X = Cl, Br) with 4-acetylpyridine thiosemicarbazone (HL^H) and derivatives in which the thioamide nitrogen bore Me or Ph (HL^Me and HL^Ph, respectively). In these complexes, which were characterized by X-ray crystallography and FAB, IR and ¹H NMR spectroscopies, the thiosemicarbazone ligands bridge between two rhenium atoms by coordination of their N_pyridine and S atoms. This coordination mode is unusual in that it does not involve any of the thiosemicarbazide nitrogen atoms. The isolation of dimeric complexes rather than monomers or polymers seems to have been due to their poor solubility and rapid precipitation from the reaction medium. [Re₂Cl₂(CO)₆(HL^H)₂] (1a) was isolated in unsolvated form and as its acetone and acetonitrile solvates; [Re₂Br₂(CO)₆(HL^H)₂] as its methanol solvate; and all the other complexes as acetone solvates. In all the solvated crystals except those of [Re₂Cl₂(CO)₆(HL^Ph)₂] (3a), all the solvent molecules are hydrogen-bonded to the complex, and in those of [Re₂X₂(CO)₆(HL^H)₂] these hydrogen bonds contribute significantly to the cohesion of the structure (in particular, in [Re₂Br₂(CO)₆(HL^H)₂]·2CH₃OH there are no hydrogen bonds directly linking the dimers). In 3a·2(CH₃)₂CO the dimers are linked by N–H⋯π and C–H⋯O interactions, and the non-hydrogen-bonded solvent molecules occupy channels with interatomic long and short diameters of 8.5 and 5.6 Å, respectively.