[en] Mononuclear, homo, hetero-dinuclear and tetranuclear lanthanide (III) and uranyl (VI) complexes with macroacyclic Schiff bases, derived by condensation of salicylaldehyde or 2.3-dihydroxybenzaldehyde with 1.4-bis[bis(2-aminoethyl)aminomethyl]benzene have been prepared. Their properties have been compared with those of the similar mono-homo and heterodinuclear complexes containing uranyl(VI) and/or lanthanide(III) ions with the potentially heptadentate compartmental Schiff base obtained by condensation of 2.3-dihydroxybenzaldehyde with 1.5-diamino-3-azapentane. The ligands and the complexes have been characterized by i.r., ¹H and ¹³C n.m.r. spectroscopy and mass spectrometry measurements. Their physico-chemical properties have been correlated with their structures, determined by single crystal X-ray diffractometry