A new lanthanide metal-organic framework (MOF) [Eu(BTB)(phen)(DMF)]DMF (1, DMF = N,N-dimethylformamide) was synthesized using H₃BTB (1,3,5-tri(4-carboxyphenyl)benzene) and phen (1,10-phenanthroline) under solvothermal conditions. The structure of the prepared MOF was characterized by single-crystal X-ray diffraction analyses, elemental analysis, fluorescence spectrum, FT-IR spectroscopy, powder X-ray diffraction and thermogravimetric analyses. The structure of 1 can be viewed as a 3-D supramolecular network, which is formed by the stacking of 2D layers through π-π interaction. The luminescence explorations revealed that 1 possesses favorable selectivity and sensitivity for testing Fe³⁺. Additionally, color tuning was achieved by varying Eu³⁺:Tb³⁺ ratios in the reaction mixtures.