Promoting the feasibility of carbon films as electrode applications requiressufficient performances in view of both electrical and mechanical properties.Herein, carbon films with ultrahigh electrical conductivity and mechanicalmodulus are prepared by high temperature carbonization of polyacrylonitrile(PAN)/single-walled carbon nanotube (SWNT) nanocomposites. Achievingboth performances is ascribed to remarkable graphitic crystallinity, resultingfrom the sequential templating–coalescing behavior of concentrated SWNTbundles (B-CNTs). While well-dispersed SWNTs (WD-CNTs) facilitate radialtemplating according to their tubular geometry, flattened B-CNTs sandwichedbetween carbonized PAN matrices induce vertical templating, where theformer and latter produce concentric and planar crystallizations of thegraphitic structure, respectively. After carbonization at 2500°C with theremaining WD-CNTs as microstructural defects, the flattened B-CNTscoalesce into graphitic crystals by zipping the surrounding matrix, resulting inhigh crystallinity with the crystal thicknesses of 27.4 and 39.4 nm for the (002)and (10) planes, respectively. For comparison, the graphene oxide (GO)containing carbon films produce a less-ordered graphitic phase owing toirregular templating, despite the geometrical consistency. Consequently,PAN/B-CNT carbon films exhibit exceptional electrical conductivity (40.7×104Sm−1) and mechanical modulus (38.2±6.4 GPa). Thus, controlling thetemplating−coalescing behavior of SWNTs is the key for improving finalperformances of carbon films.