A number of three ring diesters based on 4’-n-alkoxy- and 4’-n-alkyl-biphenyl-4-ylpropanoic acid have been prepared to investigate the effect on the liquid crystalline behaviour of these compounds of(a) incorporation of branched (achiral) end groups, and (b) laterally positioned fluorine atoms. Many of these diesters exhibited wide temperature range S-C and S-I phases, especially for compounds containing the 2-methylpentyl end group. Lateral fluorination in both the 2- and 3-positions of the phenolic moiety reduced the melting point and smectic thermal stabilities of the diesters. The reduction in S-C thermal stability by incorporation of a laterally positioned fluorine atom in the 2-position was very small, giving rise to compounds with very wide S-C ranges (40-50 degrees C). Unexpectedly, compounds containing a laterally positioned fluorine atom in the 3-position gave a number of crystal phases. Whether the diesters incorporated a branched terminal group or a laterally positioned fluorine atom, no nematic phase was observed.