The synthesis and complexation to Eu(III) of two macrocyclic ligands functionalized donor-phenylethynyl-moieties as sensitizer is presented The two ligands based on DTPA bis-amide ([Eu(L(1))]) and DO3A ([Na][Eu(L(2))]) have been chosen because of their increased stability in water for potential applications as luminescent bioprobes for one- or two-photon excited scanning microscopy The DTPA and DO3A ligands possess oxygen or sulfur donor atoms, respectively, connected to a tnethyleneglycol (PEG) chain to ensure the water solubility. The optical properties were studied and reveal that ((Eu(L(1))1) present a lower brightness than the ([Nal[Eu(L(2))]) counterpart because of its inner sphere water molecule coordination that quenches the emission On the other hand, [NallEu(1.2)1 exhibits excellent spectroscopic properties with high quantum yield phi = 0.284, and brightness B = 10,220 M(-1)cm(-1)(defined as epsilon.phi) Unfortunately, the two-photon cross-section of this last complex was measured to be only 4 GM limiting its potential applications to linear microscopy. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved. R SUM