Ligands, where two terpyridine units are linked via an alkyl chain of three to five methylene units, have been synthesized. Their Cu2+ complexes have been studied as catalysts for the hydrolysis of the triphosphate bridge of three different dinucleoside triphosphates. The results show that the bimetallic complexes are up to 600 times more efficient catalysts than monomeric Cu2+-TerPy, and up to 5 x 10(5)-fold rate enhancement in comparison to the uncatalysed reaction, is achieved. However, the catalytic activity strongly depends on the length of the linker and the base composition of the substrate. The differences can be attributed to interactions between the Cu2+-TerPy and nucleic acid base moieties as well as steric factors that may hinder the productive interaction between the substrate and the catalyst.