We describe the synthesis and characterization of a Cu(I) complex, {Q₃Sb(o-chlor)}Cu(OTf) (Q = 8-quinolinyl; OTf = trifluoromethanesulfonate; o-chlor = o-choranil), supported by the Sb(V) ligand Q₃Sb(o-chlor). The complex {Q₃Sb(o-chlor)}Cu(OTf) was experimentally characterized via ¹H, ¹³C{¹H}, and ¹⁹F{¹H} NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) as well as examined computationally with density functional theory (DFT) calculations. Variable temperature ¹H NMR spectroscopy (20 to −110 °C) indicates temperature-dependent fluxional processes for {Q₃Sb(o-chlor)}Cu(OTf) and uncoordinated Q₃Sb(o-chlor). The electron density of Cu for {Q₃Sb(o-chlor)}Cu(OTf) was probed by comparing Cu^II/Cu^I redox potential and Cu 2p electron binding energies, using XPS, with a related non-Sb-containing complex, (TMQA)Cu(OTf) (TMQA = tris(quinolin-2-ylmethyl)amine). The E_1/2 of the Cu^II/Cu^I redox of {Q₃Sb(o-chlor)}Cu(OTf) is shifted 670 mV more positive than that of (TMQA)Cu(OTf). XPS spectra of {Q₃Sb(o-chlor)}Cu(OTf) and (TMQA)Cu(OTf) indicate a 0.8 eV higher Cu 2p binding energy for {Q₃Sb(o-chlor)}Cu(OTf). Computational studies of the molecular orbitals and localized natural bonding orbitals (NBOs) are consistent with a weak Cu(I) → Sb(V) interaction for {Q₃Sb(o-chlor)}Cu(OTf), for which Sb(V) acts as a Z-type ligand.