In the title compound, [Co(C(6)H(5)N(4))(3)], the Co(III) atom adopts a distorted octa-hedral CoN(6) coordination geometry, arising from three N,N'-bidentate deprotonated 2,2'-biimidazole ligands. The dihedral angles between the five-membered rings of the ligands are 4.1 (2), 9.4 (2) and 10.5 (2)°. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds, generating a layered network lying in (11).