In this study, we have demonstrated a two-legged, upright molecular design method for monochromatic and bright red luminescent Ln III -silica nanomaterials. A novel Eu IIIsilica hybrid nanoparticle was developed by using a doubly binding TPPOÀ Si(OEt) 3 (TPPO: triphenyl phosphine oxide) linker. The TPPOÀ Si(OEt) 3 was confirmed by 1 H, 31 P, 29 Si NMR spectroscopy and single-crystal X-ray analysis. Luminescent Eu(hfa) 3 and Eu(tfc) 3 moieties (hfa: hexafluoroacetylacetonate, tfc: 3-(trifluoromethylhydroxymethylene)camphorate) were fixed onto TPPOÀ Si(OEt) 3 -modified silica nanoparticles, producing Eu(hfa) 3 (TPPOÀ Si) 2 -SiO 2 and Eu(tfc) 3 (TPPOÀ Si) 2 -SiO 2 , respectively. Eu(hfa) 3 (TPPOÀ Si) 2 À SiO 2 exhibited the higher intrinsic luminescence quantum yield (93 %) and longer emission lifetime (0.98 ms), which is much larger than those of previously reported Eu III -based hybrid materials. Eu-(tfc) 3 (TPPOÀ Si) 2 À SiO 2 showed an extra-large intrinsic emission quantum yield (54 %), although the emission quantum yield for the precursor Eu(tfc) 3 (TPPOÀ Si(OEt) 3 ) 2 was found to be 39 %. These results confirmed that the TPPOÀ Si(OEt) 3 linker is a promising candidate for development of Eu III -based luminescent materials.