The research entailed the Synthesis and Charactensation of a range of Molecular Receptors The target receptor was a calix[4]arene denvative, possessing a tetrahedral ’pocket’ at the lower rim defined by four p endant ligating groups, with opposing groups differing in length To achieve this, the spacer units in th e 1,3 positions of th e calixarene must differ in length than the spacer units in th e 2,4 positions by a single methylene spacer, thus generating a selective 3 - dimensional binding site. LC-UV-MS analysis of the products of the denvatisation of p-t-butyl calix[4]arene with ethyl bromo acetate has been earned out in order to optimise the synthesis of th e 1,3 disubstituted product LC-DAD and LC-UV-MS methods have been developed to successfully identify and characterise the compounds being formed in these complex reactions Obtaining reliable routes to partially substituted calixarene denvatives is of growing interest a s they provide a template for generating complex denvatives with mixed functionality and/or greater diversity. The synthesis has led to the generation of a series of partially substituted calix[4]arene denvatives, as well as derivatives of the tetrahedrally arranged target receptor. The various receptors have been assessed for lon-complexation properties by a number of methods, pnncipally NMR spectroscopy, an d ion-selective electrode stud ies In th e electrode measurements, the receptors are dispersed in a plasticised PVC membrane, and the lon-selectivity of the device is assessed. Patterns related to the selectivity of Group I, II ions an d a diverse group of anions have been determined The 1,3-diester produces a sensor that exhibits a Nernstian Response with a number of ions, but d o e s not reproduce th e well-known selectivity of th e calix[4]arene tetra esters Functionalisation at the 2,4 position with ethyl 3-bromopropionate realises a calix[4]arene denvative with differing spatial a rran g em en ts of differing binding sites, a novel diacid, d ieste r calix[4]arene denvative (fig 1) This will provide a unique platform for building a new s e n e s of calix[4]arene receptors with tetrahedral rather than an octahedral arrangement of binding sites