The preparations are reported of some new complexes with 2,5-dithiahexane and 1,2-di-(isopropylthio)ethane as ligands, and physical measurements, including infrared spectra in the range 200–500 cm.–1 are reported for these, and for some previously known complexes of 2,5-dithiahexane. The magnetic properties of Co(dithiahexane)2(ClO4)2 can be explained in terms of a doublet–quartet equilibrium. Adducts formed by the nickel complexes of 2,5-dithiahexane with molecular iodine are reported, and their nature is discussed.