Syntheses and X-ray structure analyses of two new tetradentate ligands with “oxime-and-amide” donor systems (N,N′-bis(2-hydroiminopropionyl)-1,2-diaminoethane and N,N′-bis(2- hydroxyiminopropionyl)-1,4-diaminobutane) were performed. The overall conformation of both ligands is distinctly different from that reported earlier for N,N′-bis(2-hydroxyiminopropionyl)- 1,2-diaminopropane. The number of methylene groups critically influences the ligand geometry and may have distinct impact on the co-ordinating ability of the ligands.