The synthesis of the macrocycle 2,5,8,17,20,23-hexathia[9,9]-p-cyclophane (p-S6) and its dicopper(I) complex [Cu2(p-S6)(CH3CN)2](BF4)2 are reported. The single crystal X-ray structure of the complex was determined and compared with related compounds. The structure shows a centrosymmetric cation with two tetrahedral copper(I) centres each coordinated to three S-donor atoms [Cu - S distances between 2.287(2) and 2.349(2) Å] of p-S6, and to one acetonitrile molecule [Cu - N = 1.897(6) Å], to give a NS3 environment around the metal ion. Molecular dynamics simulations show that p-S6 is a flexible macrocycle with no particular conformation strongly favoured. Copyright © 1996 Elsevier Science Ltd.