Wurtzite gallium nitride microscale tubules were synthesized through chemical vapor deposition method. The tubules were self-assembled from nanorods without any templates. The self-assemblies were up to 100 mu m long and 10 mu m in diameter. The tubules were porous. The unique structures of the tubules caused red-shifts of Raman modes and yellow band in photoluminescence spectra. A possible growth mechanism of the porous microtubules was proposed based on experimental observations. (C) 2015 Elsevier B.V. All rights reserved.