A novel two-dimensional supramolecular complex, Mn(HA)2(H2O)2 (1) (H2A: 9-ethylcarbazole-3,6-dicarboxylic acid) has been prepared by hydrothermal synthetic method and characterized by X-ray single crystal diffraction, IR spectra, elemental analysis and TG analysis. The result confirms that complex (1) crystallizes in the space group C2/c with a = 31.30(2) Å, b = 5.088(4) Å, c = 20.517(14) Å, β = 119.863(9)°, Z = 4, V = 2834(3)Å3. The 2D supramolecular open framework (1), which contains 9.773 × 7.447 Å nanometer channels, is constructed through hydrogen bonds and aromatic π − π interactions. Furthermore, the solid-state fluorescent analyses show that complex 1 exhibits a broad emission with the maximal emission at 416 nm.