A process for producing a highly oriented graphitic film, consisting of (a) preparing a dispersion having graphene oxide (GO) or chemically functionalized graphene (CFG) dispersed in a liquid to form a liquid crystal phase (but not in a GO gel state); (b) depositing the dispersion onto a supporting substrate to form a layer of GO or CFG under an orientation-inducing stress; (c) removing the liquid to form a dried GO or CFG layer having an inter-plane spacing d002 of 0.4 nm to 1.2 nm; (d) thermally reducing the dried layer at a first temperature higher than 100° C. to produce a porous layer of reduced GO or CFG; (e) further heat-treating the porous layer at a second temperature to produce a porous graphitic film having an inter-plane spacing d002 less than 0.4 nm; and (f) compressing the porous graphitic film to produce the highly oriented graphitic film.