We next study the loss of oxygen atoms from the terminal/lateral methoxy group(s) of RM734 and compound 1. Compound 3, in which the terminal (4-) methoxy group is replaced with a methyl group has only a modest reduction in TN F -N, a sharp reduction in TN-Iso and a modest increase in melting point. Compound 4 is closely related to 3, having both the terminal and lateral methoxy groups replaced with methyl; however, the mesomorphic behaviour of 4 is rather different, with this material only exhibiting a conventional nematic phase. To a first approximation, this can be understood to be a consequence of the reduced dipole moment that results from the loss of the lateral methoxy group, and we will demonstrate this shortly (inter alia). In 5 we add an additional methyl group to 4 in the 2-position (or alternatively, we replace the methoxy units of 1 with methyl); with the resulting material exhibiting a conventional nematic phase.