A new tripodal O-donor ligand, tris(2-N,N-dibutylcarbamoylmethoxyphenyl) phosphine oxide (L), was synthesized. This potentially tetradentate ligand L exhibits variable denticity upon complexation with UO 2 (NO 3 ) 2 , Nd(NO 3 ) 3 , and Lu(NO 3 ) 3 . The complexes were studied by elemental analysis, IR, and 1 H, 13 C, and 31 P NMR spectroscopy.