The strained cycloheptynes 2a, 2b and 2c react with copper(I) chloride to form the dinuclear complexes [CuCl(cycloheptyne)]23a, 3b and 3c respectively. X-ray diffraction studies on all three compounds 3 show an increase in strength of the copper-alkyne bond with increasing deformation of the alkyne moiety from the ideal 180°. Thus going from the least strained alkyne (2c) to the most strained one (2a)