Abstract DDAD· AADA heterodimers based on the structures 8 and 9 have been synthesised and characterised. Solubility problems have been overcome through the introduction of a 2, 6-dimethylphenyl substituent (8c), and association constants K ass have been determined by 1 H NMR titrations. The K ass values obtained could be confirmed by osmometry, as could the association constants for other heterodimers. The K ass value increases when ...