Two series of oxa-amide ionophores based on 2-phenylglycerol and cis-cis- 1,3,5-cyclohexanetriol with ligand coordination numbers of 4, 5 and 6 have been synthesised and studied. Complexation of the ligands with group Ia and IIa metal ions was studied using IR, (^13)C NMR and electrospray mass spectroscopy. Potentiometric membrane electrodes have been prepared and their performance evaluated using a fixed interference method. Ionophores based on the hexadentate cyclohexyl triamide show excellent Na(^+)/K(^+) selectivity (-logK (^pot)(_Na,K) = 3.1), and the pentadentate analogue shows good Li(^+)Na(^+) selectivity (-logK (^pot)(_Na,K) = 2.2), Ligands based on 2-phenylglycerolexhibited good Ca(^2+) selectivity which was highest for the hexadentate triamide. The attempted synthesis of two 14-crown-4 fluorophores is reported as well as the synthesis and evaluation of an 18-crown-6 based fluorophore. The 18-crown-6 fluorophore shows a bathochromic fluorescent shift in the presence of potassium ions. Additionally a fluorophore was prepared based on a tri (napthylmethyl oxaamide) derivative of cis-cis-1,3,5-cyclohexane and its fluorescence characteristics assessed. A reduction in fluorescence intensity was observed with increasing concentrations of calcium and sodium ions.