Poly(p-vinylphenol) (PVPh) and poly(N-acryloylmorpholine) (PAcM) form interpolymer complexes in ethanol/water (1:1) solution. However, only ordinary blends are obtained from dimethylformamide solution. Each of the complexes and ordinary blends shows one composition-dependent glass transition temperature, indicating its single-phase nature. Fourier transform infrared spectroscopy and C-13 solid-state nuclear magnetic resonance spectroscopy reveal the existence of hydrogen-bonding interactions between the hydroxyl groups of PVPh and the carbonyl groups as well as the ether oxygen of PAcM in the blends and complexes. In addition, X-ray photoelectron spectroscopy shows that the nitrogen atoms in PAcM are also involved in hydrogen-bonding interactions. Measurements of proton spin-lattice relaxation time in the rotating frame, T-1rho(H), reveal that each of the complexes and ordinary miscible blends has one composition-dependent T-1rho(H), indicating an intimate mixing on a scale of about 1.5 nm. The blends show a higher degree of surface enrichment of PVPh than the complexes.