The mesomorphic behaviour of both complexes, determined by a combination of polarised optical microscopy (POM) and differential scanning calorimetry (DSC), are given in Table . Transition temperatures (T, °C) and associated enthalpies (ΔH, kJ mol -1 ) for the complexes 1 (RM733.4NPy) and 2 (RM733.3F4NPy). Transition temperatures for the analogous parent covalent materials RM734 and RM734-3F are given, above. # Transition observed by POM only. * The complex begins to decompose at ~ 250 °C Both complexes display significant increases in melting point when compared to the parent materials. Both complexes melt directly into the isotropic liquid, and on cooling exhibits two distinct nematic phases. The upper temperature phase is a conventional nematic, whereas the lower temperature phase is a ferroelectric nematic (vide infra). The higher temperature (apolar) nematic phase displays a characteristic schlieren texture (Fig. ), which becomes grainy at the NF-N transition (Fig. ), while the lower temperature (polar/ferroelectric) nematic phase displays a schlieren texture with a modest change in birefringence (Fig. ). Microscopy studies of complexes 1 and 2 are consistent with those on other NF materials. Complex 1 has a wider nematic phase range than the fluorinated complex 2, mirroring the behaviour of the parent systems. The fact that supermolecular systems can display the NF phase is encouraging, nevertheless it must be acknowledged that, in the present case, the onset temperature of the NF phase is far below the melting point, which renders detailed characterisation of these complexes virtually impossible. We constructed a phase diagram for binary mixtures of each complex in turn with RM734 (Fig. ) in order to validate our phase assignment of both phases. Both supermolecular complexes are miscible with RM734 across the entire phase diagram, with the onset temperatures of the nematic and NF phases varying approximately linearly with concentration (Fig 3d ), confirming the earlier phase assignment made by microscopy. We performed geometry optimisations for both complexes at the counterpoise corrected B3LYP-GD3BJ/6-31G(d,p) level of DFT, as well as for the analogous covalently bonded materials (RM734 and RM734-3F). For the hydrogen-bonded systems we also employ counterpoise correction in our DFT methods. Our calculations show that complexes 1 and 2 have smaller dipole moments than the parent systems (Table ). The angle between the dipole vector and the long axis (β) also being somewhat larger for the complexes than the covalently bonded systems. As expected, the anisotropy of polarizability in 1 and 2 is reduced, relative to the parent compounds, owing to the fact that the aromatic core units are not covalently bonded. The increased molecular length of complexes 1 and 2 relative to RM734/RM734-3F leads to marginally higher values of the shape anisotropy parameter (ShAP). While the molecular electric dipole moment does not govern the incidence of the NF phase in isolation, the magnitude of the reduction in the hydrogen-bonded complexes, relative to the parent systems, is very much consistent with the reduction in TN-NF seen for complex 1. More surprising is that complex 1, whose dipole moment is only around 25% larger than that of 5CB (~ 4.5 D), is capable of sustaining the polar order that generates the NF phase at all, albeit at a very significantly reduced onset temperature to the covalently bonded parent material. Dipole moment (µ, Debye), dipole angle (β, °), and anisotropy of polarizability (Δα, Å 3 ) for complexes 1 and 2, along with the parent covalent materials RM734 and RM734-3F, as calculated at the B3LYP-GD3BJ/6-31G(d,p) level. Shape Anisotropy Parameter (ShAP) defined here as 𝑙/√(𝑤𝑏), where 𝑙/𝑤/𝑏 are the molecular length, width, and breadth, respectively.