A conducting thin layer of aligned fibrous nano-crystallites of tetrathiafulvalene–7,7,8,8,-tetracyanoquinodimethane (TTF–TCNQ) is fabricated directly on semiconducting organic crystals under ambient conditions. The widths of the crystallites are 50–100 nm. Their growth direction is governed by the direction of the intermolecular charge transfer interactions in the substrate crystal. The carrier transport in the film is metallic between 150 K and 300 K, reflecting the uniform alignment of the TTF–TCNQ nano-crystallites on the substrate crystal.