Two Cd(II) metal-organic frameworks (MOFs), namely, [Cd(L1)(1,4-NDA)]_n (1) and [Cd₂(L2)(TDCA)₂(H₂O)₂·0.5CH₃CN]_n (2) (L1 = 1,4-bis(1-(piperidin-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)butane, L2 = 1,4-bis(5,6-dimethyl-1-(pyridin-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)butane, 1,4-H₂NDA = 1,4-naphthalenedicarboxylic acid, H₂TDCA = 2,5 thiophenedicarboxylic acid) were synthesized and characterized. 1 exhibits a 3D dia topology and 2 shows an unprecedented 3D new topology, respectively. Both 1 and 2 behave remarkable chemical stabilities and can be used as good fluorescence sensors for the sensing of Fe³⁺ with high sensitivity and selectivity. 1 and 2 have shown fluorescent detection capabilities for enrofloxacin and nitrofurazone, which are rarely reported in previous literature. Furthermore, the mechanism of fluorescence quenching was explained.