The design of coordination polymers with various dimensionalities (1-D, 2-D, 3-D) represents a hot topic in crystal engineering. The interest in such systems arises from their exciting properties, as well as their potential applications in various fields: catalysis, molecular magnetism and multifunctional molecule-based materials, separation and storage of specific molecules. We are currently developing new synthetic approaches leading to homo- and heterometallic coordination polymers. A special emphasis is given to homometallic crystals featuring large cavities or channels able to accommodate various guest molecules. We obtained such systems using classical spacer molecules (e. g. hexamethylenetetramine – Figure 1), or more sophisticated, specially designed, divergent ligands. On the other hand, the combination of two or three different paramagnetic ions within the same molecular entity is particularly important in molecular magnetism. Several recent examples of heterotrimetallic coordination polymers synthesized in our Laboratory and showing Single Chain Magnet behaviour will be presented.figureFigure 1. Perspective view of a porous crystal Figure 2. View of heterotrimellic, CuII -TbIII -WV, Single Chain Magnet.