Four new, non-interpenetrated square-grid coordination polymers, namely [Mn(L)(2)(NO3)(2)](infinity) (1), {[Cd(L)(2)(NO3)(2)]center dot solvate}(infinity) (2), [Cd(L)(2)(NO3)(2)](infinity) (3), and {[Zn(L)(2)](BF4)(2)center dot(C6H6)(2.564)center dot(DMF)(1.576)center dot(MeOH, H2O)(3.454)}(infinity) (4), were synthesized using the new, extremely long N,/N'-type ligand: 2,5-bis(4'-(imidazol-1-yl)benzyl)-3,4-diaza-2,4-hexadiene (L). The reaction of Cd(NO3)(2) with L leads to two novel structures sharing the same framework composition, [Cd(L)(2)(NO3)(2)](infinity) which have different arrangements of L around the metal centers. Both the channel-containing structure and the nonporous structure can be formed by choice of the appropriate solvent system. Moreover, the less stable, channel-containing form readily converts into the more stable, condensed structure upon removal of the guest molecules from the channels.