Three new homoleptic six-coordinate Sm(III) complexes have been synthesized from diketone ligand with different substituent groups. The structural properties of these compounds have been investigated using elemental analysis, UV-Vis, and FT-IR approaches. Then, their photoluminescence properties of the synthesized Sm complexes have been examined.Also, the cytotoxic activities of the complexes have been studied against to human epidermoid carcinoma cell (HTB-54) and normal bronchus epithelial cell (BEAS-2B). According to result, the [Sm(MPBP-1,3PPon)3]·H2O) (IC50: 11.05 μM) complex was more active than [Sm(BMP-1,3PPon)3]·2H2O (IC50:58.64 μM) and [Sm(BCP-1,3PPon)3]·H2O (IC50: >500 μM) complexes. Otherwise it was no effect on normal cell (BEAS-2B). This result shows that complex [Sm(MPBP-1,3PPon)3]·H2O) has the potential to be the ideal chemotherapeutic drug.