The crystal and molecular structure of [{Cu₂(OMe)₂(tftbd)₂}₃][tftbd = 4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate] has been determined from single-crystal X-ray diffraction data and refined to R 0.058 for 3 241 independent reflections. The compound crystallizes in the triclinic space group P with one hexameric molecule in a cell of dimensions a= 11.212(7), b= 11.079(7), c= 15.315(9)Å, α= 92.71 (5), β= 116.80(5), and γ= 95.56(5)°. The molecule consists of three roughly planar methoxo-bridged dimeric units: a centrosymmetric ‘dimer’ with average Cu–O 1.94(1)Å and Cu–O–Cu 99.5(3)° within the Cu₂O₂ bridging group, and two inversion-related non-centrosymmetric ‘dimers’ having a slightly non-planar Cu₂O₂ group with Cu-O ranging from 1.90(1) to 1.96(1)Å and two different Cu–O–Cu angles, 98.9(3) and 102.8(3)°. The dimers are joined by axial copper-oxygen bonds. The geometry around the copper atoms is approximately square pyramidal. Magnetic susceptibility data in the range 4.2–350 K indicate overall antiferromagnetic spin coupling. The magnetism of the complex can be explained using the isotropic Heisenberg–Dirac–van Vleck model for three non-interacting dimers. The resulting values for the exchange parameters indicate a stronger antiferromagnetic interaction in the non-symmetric ‘dimer’(J=–440 cm^–1) than in the centrosymmetric one (J=–214 cm^–1). The magnetism of both ‘dimers’ is discussed in relation to the structural data.