The difference in chain arrangements between ordinary miscible blends and polymer complexes could be monitored by a nonradiative energy transfer (NRET), when part of one of the constituents, i.e., poly(methyl methacrylate) (PMMA), was labeled with fluorescence donor (c) and another part with acceptor (a). In blends composed of PMMA-a, PMMA-c, and modified polystyrene [PS(OH)] carrying hexafluoro-alpha-hydroxypropyl groups, a gradual decrease of the energy transfer efficiency was observed accompanying the transition from miscibility to the pairing of interacting polymer chains as the hydroxyl content in PS(OH) increases, from 2 to 10 mol %. Solid-state H-1 NMR relaxation measurements failed to reflect the transition. However, evidence of complexation between PMMA and PS(OH) with a high hydroxyl content was obtained by NMR NOE measurements in the blend solutions.