The present invention relates to compounds that are useful as metal ligands and which can be bound to a biological entity such as a molecular recognition moiety and methods of making these compounds. Once the compounds that are bound to a biological entity are coordinated with a suitable metallic radionuclide, the coordinated compounds are useful as radiopharmaceuticals in the areas of radiotherapy and diagnostic imaging. The invention therefore also relates to methods of diagnosis and therapy utilizing the radiolabelled compounds of the invention.