3D nanoporous coordination framework [Ni2(nic)4(H2O)]n (nic=Nicotinic acid) was obtained hydrothermally from a mixture of NiCl2.6H2O and 3-cyanopyridine. X-ray single crystal analysis revealed that it consists of “mushroom-shaped” channels along a axis suitable for gas storage. N2-adsorption studies at 77 K revealed a Langmuir surface area of 200 m2/g and a pore volume of 0.12 cm3/g. The compound shows dynamic dehydration and rehydration behaviors with the formation of 0D coordination [Ni(nic)2(H2O)4], accompanied by crystal-to-crystal transformation. The structural transformation significantly changes the character of magnetic exchange interactions and gas storage.