Crystals constructed by hydrogen bonded molecules can be viewed as having nanostructural elements consisting of ordered, supramolecular hydrogen bonded networks. These networks, whose dimensionalities and motifs are governed by the molecular structure and hydrogen bonding topology of their components, can serve as buildingblocks in the design and synthesis of molecular materials. Robust supramolecular buildingblocks can reduce significantly the number of possible solid state packing motifs, a key goal of crystal engineering strategies which aim to design and synthesize molecular solids with controlled solid state structure and properties. One route to obtain materials with special and novel properties consist in the design of solid state structures by cocrystalization of suitable molecules. The chosen buildingblocks which should be connected via hydrogen bonds were 1,4-diaza-components and bifunctional hydrogen bond donors. Phenazine and substituted 1,4-diaza-1,3-butadienes are the used diazacomponents whereas the bifunctional hydrogen bond donors are substituted meso-1,2-ethanediols, aromatic diols, dicarboxylic acids and 5,10-dihydrophenazine. The 1:1 cocrystalization of these molecules leads to various supramolecular networks. In most cases 1:1 cocrystals are obtained but there are also solid state strutures with 1:2, 1:3 and 2:3 compositions. Several of them show interesting new properties which cannot only be described by the addition of their single properties, e.g thermally reversible photochromism.