Co(NO3)2, N carbazolyacetic acid and 4,4′ bipyridyl can give rise to a novel coordination polymer [Co2(Cabo)2(NO3)2(4,4′ bipy)2]n using a fritted U tube. Single crystal X ray diffraction displays in the complex, each Co? is six coordinated by two N atoms from different 4,4′ bipyridyl ligands, two O atoms of the bridge from two N carbazolyacetic acid and two O atoms of one nitrate anion to form a distorted octahedral. Two O atoms of the carboxyl group act as bridge to link two Co? atoms. The resulting structure is a ladder polymer. CCDC: 211713.