A long, flexible bipyridyltype linking ligand L [(4py)–CH 2 –NH–(CH 3 )C 6 H 3 –C 6 H 3 (CH 3 )–NH–CH 2 –(4-py)], which possesses two terminal 4-pyridyl groups, was prepared by reducing its parent diimine ligand (4-py)–CHN–(CH 3 )C 6 H 3 –C 6 H 3 (CH 3 )–NCH–(4-py). Four novel polymeric species based on L, [Co(L)(NO 3 ) 2 ] (1), [Zn(L)(NO 3 ) 2 ] (2), [CdL 2 (NO 3 ) 2 ] (3) and [CdL 2 (NO 3 ] 2 ](C 6 H 6 ) 2 (4), could be synthesized under solvothermal conditions. Whereas polymers 1 and 2 have a 1D zigzag-chain structure, polymers 3 and 4 have a 2D network structure. The N⋯N separation between the two pyridyl groups in L (the free ligand) is 19.871(3)Å, whereas this distance varies from 11.934(4) to 16.373(8)Å in its coordination polymers.