Abstract
Just as it is possible to use coordination compounds to try and gain insight into the nature of metallobiosites so it is also possible to use the knowledge acquired through crystallography concerning the structure of a metallobiosite to try to develop new chemistry. The aim of this lecture was to illustrate this philosophy by referring to the interplay that led to the confirmation of the dicopper site in haemocyanin and by speculating on the use of knowledge acquired concerning the dinuclear site in urease to facilitate simulation of the functioning of the site.