By employing a pyridyl-decorated dicarboxylic acid ligand, 3-(2',5'dicarboxylphenyl)pyridine acid (H(2)dcpy), a three-dimensional In3+-based metal organic framework, H3O[In-3(dcpy)(4)(OH)(2)]center dot 3DMF-4H(2)O (1), with a good chemical stability toward acid and base has been synthesized. The compound 1 shows an uncommon (3,8)-connected tfz-d; UO3 topological net based on linear In-3(COO)(4)(OH)(2) clusters and also contains onedimensional open channels. Particularly, 1 contains two types of dcpy(2-) linkers, in which the pyridyl group in one participates in coordination with the In3+ ion, whereas that in the other is uncoordinated but hangs in the inner sides of the channels as functionalized sites. Gas adsorption experiments demonstrate that 1 is able to selectively adsorb C2H2, C2H4, and CO2 over CH4. Simultaneously, 1 shows a highly selective and sensitive fluorescence detection toward Fe3+ ion in water with good recyclability.