Cyclization of 3-thiapentane-1,5-dithiol (4) as its cesium dithiolate with 1,3-dichloropropanone (1) gives in 72% yield the cyclic thioether 3,6,9-trithiadecanone (C7H12OS3, 5). Crystals are white. Crystal data for 5 at 130 K : monoclinic, space group P2(1), with a = 7.145(1) angstrom, b = 5.310(1) angstrom, c = 11.932(1) angstrom, beta = 96.57(1)degrees, Z = 2, R = 0.024, and R(w) = 0.032 for 1640 reflections (I > 3.0sigma(I)). Reaction of 4 with 1,4-dichlorobutanone (2) affords in 52% yield the nonsymmetric 3,6,9-trithiaundecanone (C8H14OS3, 6). Crystals are white. Crystal data for 6 at 100 K : triclinic, space group P1BAR, with a = 5.408(4) angstrom, b = 7.366(3) angstrom, c = 13.581(4) angstrom, alpha = 80.87(3)degrees, beta = 78.68(5)degrees, gamma = 69.79(5)degrees, Z = 2, R = 0.074, and R(w) = 0.095 for 2105 reflections (I > 2.5sigma(I)). Reaction of 4 with 1,5-dichloropentan-3-one (3) resulted in formation of 4,7,10-trithiadodecanone (C9H16O3S, 7) in 63% yield. Crystals are white. Crystal data for 7 at 298 K : orthorhombic, space group Pnma, with a = 15.4077(3) angstrom, b = 15.3536(17) angstrom, c = 4.9889(11) angstrom, Z = 4, R = 0.072, and R(w) = 0.080 for 740 reflections (I>2.5sigma(I)). Conductometric titrations of AgOTf in MeCN and THF with 5-7 showed that, dependent on solvent and concentration, in solution 1:1 and 3:2 (ligand:Ag+) adducts are formed.