The coordination complexes of the crystalline structure of cellulose ethers/Eu(III) with fluorescence emission, viz CMC/Eu(III), MC/Eu(III), and HEC/Eu(III), were synthesized and characterized. Results showed the emission spectra of Eu³⁺ ions in these coordination compounds, which originates from electric dipole transition. The main emission peak at 615 nm generated from ⁵D₀⁷F₂ transition of Eu³⁺ ions. Their absorption and excitation spectra were different, because the effect of the high polarity of water and having both hydrogen bond donor and acceptor properties on the excited molecule is different from the effect on the ground state of the molecule. Our study demonstrated that the Degree of Substitute (DS) of CMC could influence the fluorescence intensity (FI) of CMC/Eu(III). The emission intensity of CMC/Eu(III) varies with the DS of CMC. For example, when the DS of CMC was 0.89, the FS (fluorescent spectra) of solid CMC/Eu(III) displayed three emission peaks Eu(III): the strongest emission peak at 615 nm (⁵D₀⁷F₂ transition) and other two weaker peaks at 583 nm (⁵D₀⁷F₁ transition) and at 652 nm (⁵D₀⁷F₃ transition), respectively. The concentration of Eu(III) could also affect the FI of these coordination complexes. The FI of the coordination complexes peaked at 615 nm all reached maximum when Eu³⁺ concentration was at 5% (wt/wt). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 743–747, 2005