The human body presents a challenging biochemical environment against which drug molecules must be robust to maintain their structural integrity and pharmacological efficacy. Incorporating metal-ion radionuclides into the structure of drugs often requires the use of chelating ligands. Successful chelates provide optimal coordination geometry and strong metal-ligand bonding to convey high metal-ion selectivity and complex stability whilst maintaining or enhancing the pharmacokinetic properties of the targeting group. Studies also involve the application of all amenable structural, spectroscopic, electrochemical and potentiometric techniques to characterise the new molecules. Our goals are to explore metal-ion coordination chemistry and to synthesise new chelates for use in radiotracer design. Specific projects involve, i) coordination of high-valent metal-ions, ii) metal-ion complexes with non-traditional donor atoms, and iii) developing new bioconjugation methods. New chelates enter our radiochemistry program and support our aim of advancing alternative labelling strategies for radiopharmaceutical development.