Thin films of aligned single-walled carbon nanotubes (SWNTs) are a promising candidate for future electronics technology because they offer the opportunity to the preparation of high performance devices. Aligned SWNT film exhibit a large electrical anisotropy with high electrical conductivity in the alignment direction and low conductivity in the transverse direction due to large energy barriers for tunneling between adjacent SWNTs. We demonstrate that transition metal atoms inserted between the sidewalls of parallel SWNTs effectively coordinate to the benzene rings of the nanotubes and serve as a conduit for electron transfer. The atomically interconnected aligned SWNTs exhibit dramatically reduced electrical anisotropy due to the increase of the transverse conductivity of aligned SWNT thin films.