There are multiple close contacts between the ortho protons of both the pyridine and phenyl moieties of L and the Br ions of the guest (C-H•••Br-Re, ~2.5-3.7 Å), in agreement with the NMR data. The Cu II ions in 3 are 5-coordinate and square pyramidal in geometry (Cu -NL = 2.01 Å; Cu -O = 2.24 Å; cis, 88-98°; trans, 168-174°), with the triflate ions bonded in the outward facing apical sites and the Br ions of the guest occupying the positions sitting below the square plane of the Cu II ion (Cu•••Br, ~4.3 Å). The Cu•••Cu distance is now ~12.2 Å compared to ~11.5 Å in 1, again reflecting the increased interactions between host-guest when the ReBr6 2- anion is introduced.