Abstract. Two coordination polymers, namely {[Mn(2,4Ј-bpdc)-(bimb)(H 2 O) 0.5 ]·0.5H 2 O} n (1) and [Mn(4,4Ј-bpdc)(bimb)] n ·2.5H 2 O (2) [2,4Ј-bpdc = biphenyl-2,4Ј-dicarboxylate, 4,4Ј-bpdc = biphenyl-4,4Ј-dicarboxylate, and bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene], were hydrothermally synthesized by reactions of manganese(II) salt with the rigid ligand 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene and isomeric biphenyl dicarboxylate ligands. Complex 1 has an un-