The protonated forms of the new polyfunctional polyamine receptors L, containing two terpyridine units linked together by two diamine spacers, interact with the nucleotide thymidine 5'-triphosphate (TTP) to form stable adducts in aqueous solution. Both solution studies and the crystal structure of the [(H4L)HTTP]center dot 12H(2)O adduct show that tight association of the two partners is achieved by the formation of hydrogen bonds and salt bridges involving the ammonium groups of Land TTP phosphate oxygen atoms and multiple interactions of the nucleobase with aliphatic and aromatic groups of the ligand, mimicking the modes of interaction of TTP binding proteins.