New lanthanide complexes with 4,5-bis(diphenyl)phosphorany1-1,2,3-triazolate (L-), LnL(3)center dot nH(2)O (1-8) and LnL(3)-(phen) center dot nH(2)O (9-16) (Ln = La, Ce, Nd, Sm, Eu, Gd, Tb, Er), have been prepared and spectroscopically charactenzed The structures of LnL(3) center dot nH(2)O (Ln = La, Ce, Nd, Sm and Gd) were determined by X-ray crystallography The metal centers exhibit a distorted trigonal dodecahedron coordination environment with two symmetrically O,O-bidentate ligands and one unsymmetrically O,N-ligand attached to the metal; two oxygen atoms from neighbonng dimethyl sulfoxide (DMSO) molecules complete the coordination sphere. This unsymmetrical ligand coordination behavior was also identified in solution through P-31{H-1} NMR studies Photoluminescence spectroscopy expenments in CH2Cl2 for both types of complexes containing Eu(III) (6, 14) and Tb(III) (7, 15) exhibit strong charactenstic red and green emission bands for Eu(III) and Tb(III), respectively. Furthermore, NdL3 (phen) 5H(2)O (11) displays emission in the near-infrared spectral region (F-4(3/2) -> F-4(9/2) at 872 nm and F-4(3/2) -> F-4(11/2) at 1073 nm) The complexes containing 1,10-phenantroline exhibit higher quantum yields upon excitation at 267 nm, indicating that this auxiliary ligand promotes the luminescence of the complexes, however, luminescence lifetimes (tau) in this case are shorter than those of the LnL(3)center dot nH(2)O senes.