A supramolecular network polymer consisting of a pair of immiscible polymers, poly( butyl)methacrylate ( PBMA) and polystyrene ( PS), is described. A urea of guanosine ( 1, UG) and 2,7-diamido1,8-naphthyridine ( 2, DAN), which form an exceptionally strong quadruply hydrogen-bonding complex, are displayed at 1-10 mol % along the main backbone of PBMA and PS, respectively. H-1 NMR studies show heterocomplexation between UG and DAN exclusively. This high-fidelity, high- affinity supramolecular connection of two different polymer coils at the molecular level produces a polymer blend. Blends containing different weight ratios of the polymers and mole percent of the recognition units were characterized by AFM and DSC experiments with no isolated domains observed and a single glass-transition temperature ( T-g). The T-g is tunable by varying the weight ratio of the polymers in the blend. In addition, viscosity measurements, size-exclusion chromatography ( SEC), and dynamic light-scattering ( DLS) studies demonstrate the formation of a supramolecular network structure.