This paper reviews the research in progress in Oxford on the chemical, spectroscopic and redox properties of bis(thiosemicarbazonato) complexes of zinc and copper in the context of the hypoxia selectivity of the copper(II) complex. Also, covered are synthetic strategies for modified complexes with a range of functional substituents and the in vitro and in vivo characteristics of two of these derivatives are described. Finally, the synthesis of some new bifunctional macrocyclic ligands is described and some of these give Cu(II) derivatives which cannot be reduced and are therefore resistant to reductive loss of copper in vivo.