Synthetic supermol. polymers based on 2-ureido-4[1H]-pyrimidinone (UPy) display a quadruple H-bonding array. There are several tautomeric forms in which UPy can exist, allowing for both self-complementary (AADD) and complementary (ADDA) dimerization. A complementary heterocomplex is formed selectively upon addn. of diamido-naphthyridine (Napy) to a soln. of UPy. Utilizing the complementary heterocomplex, directional supermol. polymers can be made from UPy-UPy and Napy-Napy monomers or from a single Napy-UPy monomer. Self complementary and complementary dimerization also allows for the incorporation of UPy protecting groups in the synthesis of UPy-UPy and Napy-Napy macromonomers. The UPy protecting group prevents end-capping with the UPy cha...