The behaviour of the ligand 2,5-bis(pyrazol-1'-yl)-1,4-dihydroxybenzene (H-2LL) towards Rh(I), Ir(I), Rh(III) and Ir(III) complexes is reported. This compound with two OH groups might act as a neutral ligand (H-2LL), as a monoanionic ligand (HLL-) or as a dianionic ligand (LL2-). Complexes of all the three kinds have been isolated. In the case of H-2LL, the compounds are not organometallic complexes but clathrates. The crystal and molecular structure of the host-guest complex [(eta5-C5Me5)RhCl2-(muCl)2]-H-2LL (6a) is reported. Both the host and the guest have crystallographic C(i) symmetry. No metal-H-2LL chemical bonds are present, and van der Waals interactions between host and guest molecules govern the crystal packing. An heterobimetallic derivative [IrRh(eta5-C5Me5)Cl2(LL)] (7c) has been isolated.