<div><p>A new procedure developed for the synthesis and crystallization of various zinc(II) fumarate hydrate coordination polymers is described. In the first step, anhydrous Zn(II) fumarate, [Zn(C<sub>4</sub>H<sub>2</sub>O<sub>4</sub>)] (<b>1</b>), is synthesized from Zn(II) acetate and fumaric acid in methanol. Subsequently, this product is used as a starting material for growing small crystals of bis–aqua Zn(II) fumarate, [Zn(H<sub>2</sub>O)<sub>2</sub>(C<sub>4</sub>H<sub>2</sub>O<sub>4</sub>)] (<b>2</b>), triaqua Zn(II) fumarate monohydrate, [Zn(H<sub>2</sub>O)<sub>3</sub>(C<sub>4</sub>H<sub>2</sub>O<sub>4</sub>)]·H<sub>2</sub>O (<b>3</b>), tetraaqua Zn(II) fumarate, [Zn(H<sub>2</sub>O)<sub>4</sub>(C<sub>4</sub>H<sub>2</sub>O<sub>4</sub>)] (<b>4</b>), and tetraaqua Zn(II) fumarate monohydrate, [Zn(H<sub>2</sub>O)<sub>4</sub>(C<sub>4</sub>H<sub>2</sub>O<sub>4</sub>)]·H<sub>2</sub>O (<b>5</b>). All structures were determined or redetermined by X-ray structure analyses. The hitherto unknown compound <b>3</b> exhibits a zig-zag chain structure with five-coordinate Zn(II) ions.</p></div
