Two new Mn(II) coordination polymers formed with molecular formula [Mn(H2O)2(HBTC)·(H2O)] 1 and [Mn(H2O)2(4,4′bipy)(HBTC)2]·(H4,4′bipy)22, where BTC = 1,2,4-benzenetricarboxylate and 4,4′bipy = 4,4′bipydine, have been synthesized via hydrothermal approach and characterized by single crystal X-ray diffraction techniques. 1 is composed of Mn–H2O–Mn 1D chains and further the chains are linked by HBTC ligands to form a 2D network in the ab plane; 2 is constructed by Mn–4,4′bipy–Mn 1D chains along the b direction with Mn2+ ions coordinated to H2BTC and water as terminal ligands to form a 2D network. We also prepared a third compound with the molecular formula of [Mn(H2O)(HBTC)·(H2O)] which has been recently structurally reported elsewhere. The magnetic properties of the three compounds have been studied in detail under variable temperatures.