The present invention provides metal-organic materials, more specifically organometallic polymers, comprising polypyridyl organic ligands such as tetrakis(4-(pyridin-4-ylethynyl)phenyl)methane, tetrakis(4-(2-(pyridin-4-yl)vinyl)phenyl)methane, 1,3,5,7-tetrakis(4-(pyridin-4-ylethynyl)phenyl)adamantane or 1,3,5,7-tetrakis(4-(2-(pyridine-4-yl)vinyl)phenyl) adamantine, and metal ions structurally coordinated with said ligands, and having three-dimensional crystalline micro or sub-micro structure; as well as a method for the preparation thereof. These metal-organic materials are useful as adsorbents in processes for gas adsorption or separation.