A bifunctional ligand strategy for modification of the functional pores is of great significance in the structural design of metal-organic frameworks (MOFs). Herein, a new 2-fold interpenetrated "pillared-layer" 3D Co-MOF, {[Co(HL)(4,4'-bipy)]center dot DMF center dot 2H(2)O)(n) (1), was successfully synthesized by using two kinds of ligands, imidazolecarboxylic acid and pyridine. The metal- carboxylic layers are pillared by the 4,4'-bipy ligand, displaying a 3D framework with rectangular 3D channels (high BET surface of 190.9 m(2) g(-1) and maximum aperture of 3.9 angstrom) that are decorated with abundant uncoordinated N and O atoms. 1 shows good water stability and thermal stability (320 degrees C). The proper pores and active sites endowed 1 with a selective adsorption of Congo red in aqueous solution. In addition, a high CO2 adsorption capacity and an excellent CO2 chemical conversion were observed.