A series of new ligands suitable for the formation of luminescent lanthanidecomplexes in water is described. The chelates are designed for analyte labeling and play the role of fluorescent donor in homogeneous time-resolved fluorescence assays using LEDs as a light source for excitation at 370 nm. Ligands 3–7 are constructed from a coumarin nucleus, for lanthanide sensitization, and different aminomethylenecarboxy