An emerging trend toward development of metal-organic frameworks (MOF) consists in using preformed complexes as building blocks able to assemble via coordination chemistry and/or charge-assisted H-bonding. Within this framework and depending only on the experimental conditions, reactions of the [Zr(C 2O 4) 4] 4− anion with the [DabcoH 2] 2+ dication (Dabco = 1,4-diazabicyclo[2. 2. 2]octane) selectively afford the compounds {K 2(DabcoH 2)[Zr(C 2O 4) 4]}·6.5H 2O ( 1), {(DabcoH 2) 2[Zr(C 2O 4) 4]}·3H 2O ( 2), {(DabcoH 2) 2[Zr(C 2O 4) 4]}·5.5H 2O ( 3), or {K 2(DabcoH 2) 2[Zr 2(C 2O 4) 7]}·6H 2O ( 4). Three association schemes exhibiting drastically different network topologies have been characterized ranging from 1D to 3D; the fourth involving the in situ generated bimetallic {Zr 2(C 2O 4) 7} 6− moiety. For all four compounds, selective synthetic processes have been developed. In addition, compound 1 exhibits an open framework able to release solvates without collapsing. Besides the reversible sorption of small molecules like EtOH and MeCN, the open framework 1 was found to adsorb CO 2 at ambient temperature and pressure (ca. 30 cm 3 of gas g −1 at 298 K), whereas its propensity to take up H 2O from air is low.