Metal complexes of amino acids or small peptides interest biochemists. Some studies about their structures have therefore been carried out on the assumption that such complexes will act as models for the metal-binding sites on proteins. From the point of view of coordination chemistry, an amino acid can be regarded as a typical multidentate ligand which has different ligating atoms, a nitrogen atom of an amino group and an oxygen atom of a carboxyl group. The different ligating atoms can be coordinated to different metal ions such as metals having different hardness. The advantages of amino acid of being able to form a chelate ring and/or be coordinated to different metals can be used to synthesize heteronuclear and/or polynuclear complexes. Such syntheses of heteronuclear and/or polynuclear complexes continue to be an intensive and challenging area of investigation. In this article, some examples of polynuclear complexes with amino acids or peptides as a bridging ligand will be introduced and the possibility of using amino acidato complexes as potential building blocks in the formation of more complicated polynuclear arrays will be explored.