Methods and products of Transport co-polymerization ("TCP") that are useful for preparations of low Dielectric Constant (".epsilon.") thin films are disclosed. Transport co-polymerization ("TCP") of reactive intermediates that are generated from a first precursor with a general structural formula (Z).sub.m--Ar--(CX'X''Y).sub.n (VI) with a second reactive intermediate that is generated from a cage compound (e.g. Fullerenes, Methylsilsesquioxane, Hydrosilsesquioxane, and Adamantanyl) or a cyclic-compounds (e.g. Cyclo-Siloxanes and 2,2-Paracyclophanes) results in co-polymer films that are useful for making porous low .epsilon. (.ltoreq.2.0) thin films. The porous thin films of this invention consist of nano-pores with uniform pore distribution thus retain high rigidity thus are suitable for manufacturing of future ICs using copper as conductor. Preparation methods and stabilization processes for low k co-polymers that consist of sp.sup.2C--Z and HC-sp.sup.3C.sub..alpha.--X bonds are also revealed. A preparation method is achieved by controlling the substrate temperature and feed rate of the major precursors. One stabilization process includes a post annealing of as-deposited co-polymer films under the presence of hydrogen under high temperatures. The reductive annealing of these films is conducted at temperatures from -20.degree. C. to -50.degree. C. to +20.degree. C. to +50.degree. C. of their Reversible Crystal Transformation ("CRT") temperatures, then quenching the resulting films to -20.degree. C. to -50.degree. C. below their "CRT" temperatures. The reductive annealing is conducted before the as-deposited film was removed from a deposition system and still under the vacuum. "Re-stabilization" processes of co-polymer surfaces that are exposed to reactive plasma etching are also disclosed; thus, further coating by barrier metal, cap layer or etch-stop layer can be safely applied.