This thesis describes studies directed to the ring opening metathesis polymerisation (ROMP) of some fluorinated compounds using a range of well-defined initiators. Chapter 1 reviews some general aspects of olefin metathesis and ring opening metathesis polymerisation of relevance to the work described in this thesis. Topics such as piezo- and pyro-electricity and optical and electrical properties of conjugated polymers are introduced and these receive more detailed attention later in the thesis. Chapter 2 describes the synthesis, characterisation and properties of . poly(bis(trifluororaethyl)norbomadiene) in detail. The use of various initiating systems that have been used previously and the effect they have on the tacticity of the resulting polymer raicrostructure are discussed. The latter part of this chapter reviews some of the current thinking concerning the detailed mechanistic aspects of this polymerisation. Chapter 3 reviews attempts directed to an improvement in tacticity control in the synthesis of poly(bis(trifluoromethyl)norbomadiene). The synthesis and activity of the new well-defined initiators used in these studies are reported. It is shown that varying the nature of the ancillary Ligands surrounding the metal centre can have a dramatic influence on the tacticity of the resulting polymer. Chapter 4 reports studies directed to an examination of the limits of the well controlled synthesis of poly(bis(trifluoromethyl)norbornadiene). The syntheses of high trans and high cis, highly tactic poly(bis(trifluoromethyl)norbornadiene samples using well-defined initiating systems are described. It is shown that by varying the monomerinitiator ratio, samples with a wide range of molecular weights can be achieved and these are reported. Chapter 5 describes experiments concerning the ROMP of fluorinated monomers containing six membered rings. In particular ROMP studies of the monomers, 2,3-bis(trifluoromethyl)bicyclo[2.2.2]octa-2,5-diene . and 2,3- (tetrafluorobenzo)bicyclo[2.2.2]octatriene are described finally, Chapter 6 provides a summary of the work reported and outlines some ideas for future studies.