Some spectral properties and luminescence intensities of Tb 3+ chelates of substituted pyridine 2, 6 dicarboxylic acids and 4 phenyl pyridine 2, 6 dicarboxylic acid analogues were measured in some solutions (H 2O and EtOH etc.) by synergistic effect of EDTA. The substitution at the aromatic ring has a significant effect upon the observed luminescence intensities, excitation wavelengths, and lifetime of the complexes. Moreover, the changes in the environment cause great variation in those properties of certain Tb 3+ chelates. The results show that some of hte chelates (4 acetaminopoxypyridine 2, 6 dicarboxylic acid, 4 ethoxypyridine 2, 6 dicarboxylic acid and 4 methoxypyridine 2, 6 dicarboxylic acid etc.) have a stronger emission and longer lifetime at room temperature and may thus be used as perfectly sensitizers in fluorescence analysis.