Highly luminous lanthanide metal–organic gels (Ln-MOGs) can act as fluorescent probes for the detection of organic amines and can also be used to build white-light emitting materials based on the different luminescent properties of lanthanide ions. Here, we reported a Ln-MOG constructed with a 3,5-di(2′,4′-dicarboxylphenyl)benozoic acid (DPBA) ligand and Tb³⁺. Tb-MOG has an excellent fluorescence detection effect on organic amines including ethylenediamine, triethylamine, diisopropylamine and aniline in aqueous solution, and their detection limits reach a sub-ppm level. Considering the practicality, a Tb-MOG testing paper was prepared by a spin coating process, which can detect volatile organic amine vapors with good recyclability. Additionally, a single-phase white-light Tb_0.84Eu_0.16-MOG material was realized by in situ doping of Tb-MOG with Eu³⁺ and reasonably utilizing the blue emission of DPBA.