Direct electrodeposition of macroporous tin is achieved in a water- and air-stable room-temperature ionic liquid, namely, 1-ethyl-3-methylimidazolium-dicyanamide. This is the first example showing that tin nanowires interweaving into a porous structure can be obtained in ionic liquid without using any additive and template. The nanostructures, with great uniformity, high porosity, and good adhesion, were prepared by galvanostatic deposition at a current ranging from 0.3 to 1.2 mA cm(-2). Electrodeposition experiments performed in the 1-ethyl-3-methylimidazoliun-tetrafluoro borate ionic liquid under a similar condition generated granular tin rather than tin wires. (C) 2008 The Electrochemical Society.