We optimised the geometries of RM734 and compounds 1 -5 at the B3LYP/LAN2LDZ level of DFT in order to rationalise the trends in observed mesophase behaviour (Table ). Compound 1 is non mesogenic, despite being of comparable electrical polarity to RM734. In 1 the additional breadth that results from the two lateral methoxy units is reflected in a low value of the shape anisotropy parameter (ShAP). Compounds 2 and 3 both exhibit the NF phase, albeit at reduced temperature to the parent; they have comparable electric dipole moments to RM734, as well as being sufficiently anisotropic in shape to permit the formation of mesophases. Compounds 4 and 5 lack the terminal methoxy unit, and as such exhibit notably reduced electric dipole moments which are perhaps below the threshold required to exhibit the NF phase in this system.