The indium(III) complex of 9,14-dioxo-1,4,7,10,13-pentaaza-1,4,7-cyclopentadecanetriacetate has a seven-coordination geometry described as a capped trigonal prism. All seven coordination sites around the central metal ion are occupied by donor atoms from a single ligand molecule, in contrast to the corresponding gadolinium(III) and yttrium(III) complexes; the latter complexes have been reported previously to have a binuclear structure, in which each metal ion is coordinated to five donor atoms from one ligand molecule and to three from the second ligand molecule. This structural difference arises from the coordination number as well as the ionic radii of the central metal ions.