The six-step synthesis of the new podand-type ligand 6,6',6''-[methylidenetri(1H-pyrazole-1,3-diyl)]tris-[pyridine-2-carboxylic acid] (LH 3 ) is described. Reaction of LH 3 with LnCl 3 ¥ 6 H 2 O (Ln Eu, Gd, Tb) in MeOH resulted in the isolation of [LnL] ¥ HCl complexes characterized by elemental analysis, mass and IR spectroscopy. Photophysical studies of the Eu and Tb complexes in aqueous solutions revealed the characteristic luminescence features of the metal atoms, indicative of an efficient ligand-to-metal energy-transfer process. Determination of the luminescence quantum yields in H 2 O showed the Tb complex to be highly luminescent (f 15%), while, for the Eu complex, the quantum efficiency was only 2%. Excited-state-lifetime measurements in H 2 O and D 2 O evidenced the presence of ca. three H 2 O molecules in the first coordination sphere of the complexes. Investigation of the Gd complex allowed the determination of the ligand-centered triplet state and showed the ligand to be well suited for energy transfer to the metal. The luminescence properties of the complexes are described, and the properties of the ligand as a suitable complexation pocket is questioned.Introduction. ± Lanthanide complexes are currently finding a wide range of applications in numerous fields of analytical sciences. While their magnetic properties are particularly interesting for nuclear-magnetic-resonance imaging (MRI) with gadolinium [1] or europium [2] complexes, they also display unique photophysical properties [3] that make them excellent targets for applications in fields such as fluoroimmunoassays [4], time-resolved microscopy [5], or luminescent sensors [6]. The use of these complexes as luminescent probes has boosted the search for highly luminescent, H 2 O-soluble and stable compounds with particular emphasis for europium and terbium cations. Two main strategies have been developed to combine luminescence efficiency and H 2 O stability. The former one consisted of highly preorganized architectures that encapsulated the metal cation in cryptand-like molecules in which the metal was embedded in a confined volume [7]. Although this approach is expected to ensure the kinetic and thermodynamic stability of the complexes, it does not always allow for efficient shielding of the metal toward solvent molecules, and it sometimes suffers from low-yield multistep synthetic protocols for the obtention of the macrobicyclic ligands. The second approach takes advantage of the introduction of anionic functions grafted on heteroaromatic moieties to stabilize the compounds through multiple electrostatic interactions with the triply charged lanthanide cations. In addition, chelating arms can be easily introduced in podand-type scaffolds [8] or macrocyclic architectures [9] to bring a primary mode of pre-organization.As a coordination number of 9 is often found for lanthanide complexes, the introduction of three tridentate chelating arms have encountered great success, and