Two water-soluble mono-nuclear macrocyclic lanthanum(III) complexes of 2,6-diformyl-4-methylphenol with 1,3-diamino-2-propanol (C(1)) or 1,3-propylenediamine (C(2)) were synthesized and characterized by UV-Vis, FT-IR, (13)C and (1)H NMR spectroscopy and elemental analysis. C(1) complex was structurally characterized by single-crystal X-ray diffraction, which revealed that the complex was mononuclear and ten-coordinated. The coordination sites around lanthanum(III) were occupied with a five-dentate ligand, two bidentate nitrates, and one water molecule. The interaction of complexes with DNA was studied in buffered aqueous solution at pH7.4. UV-Vis absorption spectroscopy, emission spectroscopy, circular dichroism (CD) and viscometric measurements provided clear evidence of the intercalation mechanism of binding. The obtained intrinsic binding constants (K(b)) 9.3×10(3) and 1.2×10(3)M(-1) for C(1) and C(2), respectively confirmed that C(1) is better intercalator than C(2). The DNA docking studies suggested that the complexes bind with DNA in a groove binding mode with the binding affinity of C(1)>C(2). Moreover, agarose gel electrophoresis study of the DNA-complex for both compounds revealed that the C(1) intercalation cause ethidium bromide replacement in a competitive manner which confirms the suggested mechanism of binding. Finally, the anticancer experiments for the treated cancerous cell lines with both synthesized compounds show that these hydrophilic molecules need a suitable carrier to pass through the hydrophobic nature of cell membrane efficiently.