The generation of aromatic benzene, toluene, and xylene (BTX) compounds from non-petroleum feedstocks is of particular interest for chemists in the eyes of sustainability. Herein, a novel synthesis of toluene catalyzed by GaN semiconductor nanowire arrays is reported. Using methane and methanol as starting materials, the GaN nanowire arrays can synergistically facilitate the facile generation of toluene under either photo-irradiation or thermal-conditions. The detailed computational studies unveiled different mechanisms involved for the photo- and thermal-toluene synthesis.