Direct current magnetic susceptibility (χ) and magnetisation (M) studies were performed on polycrystalline samples of 1-2 in the temperature and field ranges T = 2-300 K, B = 0.1 T and T = 3-10 K, B = 0-9.0 T, respectively (Figs. ). At 300 K, the χT value of ~9.0 cm 3 K mol -1 for 1 matches the Curie constant expected for three uncorrelated Mn III ions with g = 2.0. Upon cooling, the χT product is invariant with temperature until approximately T = 8 K where it rapidly decreases to a minimum value of ~5.7 cm 3 mol -1 K at T = 2 K. The high temperature data are therefore suggestive of paramagnetism, with the low temperature decline assigned to a combination of zero-field splitting effects and/or very weak intra-and inter-molecular antiferromagnetic exchange interactions. Note that at these temperatures all three are likely to be correlated. The magnetisation data rise rapidly with increasing field, reaching a value of M = ~10.4 µB at T = 3 K and B = 9.0 T. The zero, or very weak exchange, is not surprising given that the three Mn ions are only connected to each other via the single, disordered [CO3] 2-ion lying in the centre of the cage (Fig. ; Mn•••Mn. ~5.31-5.43 Å). A simultaneous fit of the susceptibility and magnetisation data using spin-Hamiltonian (1) (without the exchange term) afforded the best fit parameters |DMn(III)| = 3.7 cm -1 and zJ = 0.01 cm -1 . The value of D is line with that expected for a Jahn-Teller distorted Mn III ion with a [MnO5] coordination sphere. 𝐻 ̂= ∑ 𝐷 𝑖 (𝑆 ̂𝑧 At 300 K, the χT value of ~19.8 cm 3 K mol -1 for 2 is slightly below the value expected for four Mn III ions and two Mn II ions (20.75 cm 3 K mol -1 ) with g = 2.0 (Fig. ). Upon cooling, the χT product is essentially invariant until approximately T = 200 K wherefrom it slowly decreases to a value of ~17.4 cm 3 mol -1 K at T = 75 K, before decreasing more rapidly below this temperature to a value of ~6.3 cm 3 K mol -1 at T = 2 K. Magnetisation data rise in a near linear-like fashion without saturating; the maximum value being M = 11.7 µB at T = 3 K and B = 9.0 T. These data are indicative of weak antiferromagnetic exchange between neighbouring metal ions. An examination of the magnetic core of 2 reveals two 'linear' and asymmetric [Mn III -Mn II -Mn III ] trimers that are not connected to each other (Fig. ). Thus, we simultaneously fitted the susceptibility and magnetisation data to a model containing three metal ions and two distinct J values to spin-Hamiltonian (1) which afforded the best fit values J1 = +0.10 cm -1 , J2 = -2.52 cm -1 , |DMn(III)| = 3.75 cm -1 . The larger (and negative) J2 value reflects the larger Mn-O(Ph)-Mn (~118° vs 109°) angles present. The signs/magnitudes of the exchange are in agreement with that found in calix [4]arene supported Mn clusters with similar Mn III -O-Mn II motifs. 10 The change from a calix [4]arene to a bis-calix [4]arene enables expansion from three Mn III -TBC [4] metalloligands in 1 to four Mn III -TBC [4] metalloligands in 2 and thus the self-assembly of a larger species. In each case the Mn III ions sit in the TBC [4] polyphenolic pockets and act as capping atoms in the prism/metallic skeleton, with the Na and Na/Mn II ions defining the vertices of the prism. The carbonate present in both structures results from CO2 fixation, with yields considerably improved through deliberate addition of Na2CO3/NaHCO3. The formation of 1 and 2 follows established binding rules in calix [4]arene coordination chemistry in which (under ambient conditions) the ligand preferentially binds Mn III ions over Mn II and Na I ions. Alongside the preferential electrostatic interaction, the tetraphenolic ligand pocket is particularly suited to accommodating four short equatorial bonds and thus the axially elongated (Jahn-Teller distorted), octahedral or square pyramidal Mn III ion. The structural similarities of 1 to [Cu and of 2 to [Cu highlights the dominant structural role played by the calix [4]arene ligands, and their ability to form both heterometallic and heterovalent cages whilst maintaining analogous topologies. Magnetic susceptibility and magnetisation measurements reveal that 1 behaves as a paramagnet -the long distances between Mn III ions connected by a single, disordered [CO3] 2-ion resulting in negligible magnetic exchange. Magnetic data for show weak antiferromagnetic exchange in the 'linear' [Mn III -Mn II -Mn III ] trimers present, with values in the range 0.10 cm - 1 < J < -2.52 cm -1 , consistent with previous TBC [4]-supported Mn III/II clusters with similar Mn III -O-Mn II bridging angles.