This article covers all the research work published until September 1998 about the coordination chemistry of 1,2,4-triazolo-[1,5-a]pyrimidine derivatives. The revision is mainly focused in the structural features of the compounds, obtained from single crystal X-ray diffraction. The references are classified according to the present metal atoms. These kind of ligands display a broad versatility when binding metal ions, monodentate binding through the endocyclic nitrogen atom at position 3 being however their main coordinating behaviour. Dimeric and polymeric structures are observed when a bidentate binding through N3–N4 or N3–N1, respectively, takes place. N1–O7 chelating binding mode has also been observed in a few cases. In some cases, dimers or polymers are also generated when the present auxiliary ligands are the ones that bridge the metal centres.