The reaction of zerovalent copper with cadmium iodide and triethanolamine (H3L) in dimethylformamide (dmf) carried out under open-air conditions afforded a novel heterometallic complex [Cu3(HL)3CdI2]2·4dmf. The crystal lattice consists of an octanuclear molecule [Cu3(HL)3CdI2]2, which has an inversion center at the midpoint of the central Cu2O2 unit, and of two non-coordinating dmf molecules. Eight metal atoms linked by alkoxide arms of triethanolamine ligands form a zigzag Cd−Cu1−Cu2−Cu3−Cu4−Cu5−Cu6−Cd chain with the separations between bridged Cu atoms in the range 2.935(2)−3.403(2) Å. The complex is further stabilized by intramolecular O−H···O hydrogen bonds. High-field electron paramagnetic resonance (EPR) spectra of the S = 1 spin state with D(S=1) = −0.843 cm−1, E(S=1) = −0.081 cm−1 were observed. Fitting the magnetic susceptibility temperature dependence by using the exchange Hamiltonian HHDVV = J1(S1S2 + S5S6) +J2(S2S3 + S4S5 )+ J3S3S4, to which terms expressing the zero-field splitting and Zeeman splitting of the ground S = 1 state were added, resulted in J1 = 68, J2 = 19, J3 = −57 cm−1. “Broken symmetry” DFT calculations correctly predicted the triplet ground state of the hexa-copper system.