By carrying out the synthesis in a special way, two novel cobalt(II) isomers of trans(O)-[Co(1-Bz-2-CH 2 OHIm) 4 ](NO 3 ) 2 (1) and cis(O)-[Co(1-Bz-2-CH 2 OIm) 4 ](NO 3 ) 2 .1.5H 2 O (2) have been separated. The crystal structures of the Co(II) isomers show the triclinic space group P1 (1) and the monoclinic space group C2/c (2). The coordination geometry around the Co atom is approximately octahedral (1) or very distorted octahedral (2) and the Co(II) ions are surrounded by four nitrogen atoms of the four imidazole rings and two oxygen atoms of the hydroxymethyl group. Two of the ligands act as a monodentate and two as a bidentate, forming the five-membered chelate ring with the central ion. The structural data obtained for the Co(II) isomers were confirmed by IR and UV-Vis spectroscopic methods.