Simple commercially available phenols have been investigated for their abilities to bind and sense anionic guests. Catechol is able to strongly and selectively bind chloride, as the O-H groups are located in positions particulariy appropriate for chelate binding of this anion. The addition of an electron withdrawing group to the catechol motif results in an increased chloride affinity. Catechol also demonstrates large electrochemical responses upon the addition of chloride and optical responses upon the addition of basic anions such as fluoride. A series of novel bis-catechol siderophore analogues has been successfully synthesised and their binding with chloride has been investigated. The affinity of ortho-substituted bis-catechol compounds for chloride was limited by the ability of the O-H groups to form intramolecular hydrogen bonds with the ortho substituent. Ortha-substituted compounds, which were able to form six membered intramolecular rings, were found to have the weakest affinity for chloride. The strongest receptor of this. type, which could bind chloride more th~n twice as strongly than catechol, was only capable of forming a seven membered intramolecular hydrogen-bonded ring. The affinity of meta-substituted bis-catechols for chloride was found to be limited, not by the ability to form intramolecular hydrogen bonds with the meta substituent, but by a lack of rigidity inherent within the structure. Simple meta-substituted catechols demonstrate chloride binding affinities comparable with catechol due to a lack of competitive intramolecular hydrogen bonds. However, the lack of rigidity within meta-substituted bis-catechols meant a well defined binding site could not be presented to the guest chloride. A series of receptors containing a tren-core have been synthesised and their anion and acid binding has been studied. Placing large organic functionality around the tren-core results in preferred binding of the smaller anions due to the formation of an extended binding cavity. Tren-cored receptors are also capable of transporting H+Crthrough a bulk organic phase. The ability to transport was based largely on receptor polarity rather than guest affinity. Finally, a preliminary investigation of transport through phospholipid bilayers was undertaken.