The luminescent europium complex Eu(phen)(2) Cl-3(H2O)(2) (phen refers to 1,10-phenanthroline) was doped in poly(methyl methacrylate) (PMMA) and polyvinylpyrrolidone (PVP), respectively. The formed composite systems with different molar ratios of C==O groups in polymers and Eu ions were characterized by X-ray diffractometry (XRD), FTIR, and photoluminescent (PL) spectroscopy and lifetime measurement. The XRD diffractograms show that the composites of PMMA/Eu(phen)(2)Cl-3(H2O)(2) and PVP/Eu (phen)(2)Cl-3(H2O)(2) have crystalline and amorphous structures, respectively, arising from different interactions between the polymers and the complex, as revealed by FTIR spectra. This leads to distinct luminescent characteristics arising from the D-5(0)-->F-7, transitions of Eu(III) ion (J = 0-4). For the composite systems of PMMA/complex, the characteristics of the emission lines change with decreasing molar ratios of C==O/Eu and approach that of the pure complex; whereas the composite systems of PVP/complex have similar spectral features, regardless of the molar ratios, differing from that of the pure complex. The polymer matrices have a substantial influence on the structure and properties of the composites. (C) 2004 Wiley Periodicals, Inc.