EIFD, LnCl3·6H2O (Ln = Sm, Tb) and ancillary ligand are developed to synthesize a sequence of six new β-diketone Sm-based and Tb-based compounds modified to enhance the photoluminescence property, namely Sm(EIFD)3(H2O)·CH2Cl2 (1), Sm(EIFD)3(bpy) (2), Sm(EIFD)3(phen)·CH2Cl2 (3), Tb(EIFD)3(H2O)·CH2Cl2 (4) and Tb(EIFD)3(bpy) (5), Tb(EIFD)3(phen)·CH2Cl2 (6) (EIFD: 1-(1-ethyl-1H-indol-3-yl)-4,4,4-trifluorobutane-1,3‑dione, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline). The crystal structures of compounds 1−6 with the lanthanide(III) ions of seven (1, 4)/eight (2, 3, 5, 6) coordinated configuration are determined by single-crystal X-ray diffraction. Different non-covalent interactions (NCIs) and their% contribution to the compounds structures and their roles in stabilizing the structure are determined by Hirshfeld surface analysis. The photoluminescence properties of compounds 1−6 by substituting the solvent H2O with bpy and phen contained nitrogen ancillary ligands are then studied experimentally, leading to a rationalization of their central lanthanide(III) ions emission lifetime.