Coordination polymers are extended structures based on coordinative bonds between regularly arranged organic linkers and metal cations. For the design of such compounds, more than a single coordination site is required. A variety of ditopic ligands such as polycarboxylates or 4,4'-bipyridyl derivatives have been employed for this purpose. For the more demanding synthetic task of incorporating two (or more) different metal cations into the same crystalline solid in an ordered fashion, ligands with inequivalent coordination sites can be employed. N donor substituted acetylacetones as shown to the right are particularly well-suited because their O and N donor sites differ with respect to Pearson hardness. This site preference for hard or soft cations allows to predict coordination quite reliably.

This review gives you an easy start:
N Donor substituted acetylacetones - versatile ditopic ligands.
M. Kremer, U. Englert; Z. Kristallogr. 2018, 233, 437-452.

Argentophilic Interactions in Two Ag Complexes of 3-(2-(Pyridin-4-yl)ethyl)pentane-2,4-dione, a Promising Ditopic Ligand.
S. van Terwingen, U. Englert; Crystals 2019, 9, 414-423.

3-(Pyridin-4-yl)acetylacetone: a donor ligand towards mercury(II) halides and a versatile linker for complex materials.
K.-N. Truong, C. Merkens, U. Englert; Acta Crystallogr. 2017, B73, 981-991.

Neutral mixed-metal coordination polymers based on a ditopic acetylacetonate, Mg(II) and Ag(I): syntheses, characterization and solvent-dependent topologies.
Q. Guo, U. Englert; Dalton Trans. 2017, 46, 8514-8523.

Controlled stepwise synthesis of a Cu-MOF: Transmetallation of a magnesium precursor to a three-dimensional framework with very high solvent content.
Q. Guo, U. Englert; Z. Krist. 2017, 232, DOI 10.1515/zkri-2017-2051.

Dynamic Uptake and Release of Water in the Mixed-Metal EDTA Complex M₃[Yb(EDTA)(CO₃)] (M = K, Rb, Cs).
K.-N. Truong, P. Müller, R. Dronskowski, U. Englert; Cryst. Growth Des. 2017, 17, 80-88.

An acetylacetonate or a pyrazole? Both! 3-(3,5-dimethyl-pyrazol-4-yl)-pentane-2,4-dione as a ditopic ligand.
Q. Guo, U. Englert; Cryst. Growth Des. 2016, 16, 5127-5135.

Decomposition of the mixed-metal coordination polymer - A preparation route of the active Ag/Yb2O3 catalyst for the deN2O process.
M. Konkol, M. Kondracka, P. Kowalik, W. Prochniak, K. Michalska, A. Schwedt, C. Merkens, U. Englert; Appl. Cat. B: Environ. 2016, 190, 85-92.

Bimetallic Coordination Networks based on Al(acacCN)₃: A Building Block between Inertness and Lability.
C. Merkens, N. Becker, K. Lamberts, U. Englert; Dalton Trans. 2012, 41, 8594-8599.

Ordered Bimetallic Coordination Networks featuring Rare Earth and Silver Cations.
C. Merkens, U. Englert; Dalton Trans. 2012, 41, 4664-4673.

Bimetallic Coordination Polymers via Combination of Substitution-Inert Building Blocks and Labile Connectors.
M. Kondracka, U. Englert; Inorg. Chem. 2008, 47, 10246-10257.