Investigations of novel low molar mass materials, synthesised at the University of Hull, which exhibit frustrated liquid crystalline phases are reported. These investigations comprised both electro-optic and X-ray diffraction studies. A series of liquid crystalline heterocyclic esters are described. The effect of heteroatom substitution on the molecular shape was investigated. It was found that the linearity of the molecular core varied significantly with different heteroatoms and that this had a marked effect on the liquid crystalline phases exhibited. In one of the materials (the selenophene compound) a small degree of relative bend in the core was seen to result in the presence of extra, highly ordered ferroelectric and antiferroelectric smectic phases below the SmC*A phase. The saturated electro-optic switching characteristics of the materials (Ps, optical tilt angle, current response time and rotational viscosity) were not greatly affected by the substitutions, with the exception of the increase in order already mentioned for the selenophene compound. Consequently, this type of modification of the core structure of the materials proved a usefiil way of optimising all aspects of the materials' properties for specific applications. A number of materials exhibiting ferro-, ferri- and antiferro-electric liquid crystalline phases were also investigated using X-ray diffraction techniques. The smectic layer spacings and molecular lengths were determined allowing a number of structure-property correlations to be discussed. From the layer spacings and molecular lengths the steric tilt angles of the materials were calculated and compared with the optical tilt angles. These comparisons yielded substantial evidence of conformational changes or intercalation occurring in the systems. The nature of the SmC* phase in some of the materials studied was questioned. It is thought likely that two of the compounds exhibit SmC*beta phases. The coupling of the Ps and tilt angle in these two compounds was found to be quite different from that expected for "typical" ferroelectric liquid crystals. The recent literature discussing the SmC*beta phase is reviewed and discussed with respect to the experimental observations detailed earlier in the thesis. A novel model for the structure of the SmC*beta phase is proposed which is consistent with the experimental observations.