Under hydrothermal conditions, we have successfully synthesized six isostructural lanthanide coordination polymers, [LnL(1.5)(H2O)(2)]center dot 1.75H(2)O (1-6; Ln = Eu, La, Pr, Nd, Sm, Gd), by the reaction of 5-methyl-1-(4-carboxylphenyl)-1H-1,2,3-triazole-4-carboxylic acid (H2L) and Ln(NO3)(3)center dot 6H(2)O. Structural analysis shows that polymers 1-6 show novel three-dimensional supra-molecular network structures. The luminescent properties for polymer 1 have been investigated at room temperature. The results have shown that polymer 1 can be used as a chemical sensor for multifunctional testing such as UO22+, Fe3+ ion detection, and small organic molecule detection because of its strong fluorescence properties. In particular, polymer 1 exhibits extremely high selectivity and sensitivity for the detection of Fe3+ ions. In addition, white-light emission is achieved through a reasonable tuning proportion by mixing Gd3+ and Eu3+.