Silicon-based preceramic polymers perhydropolysilazane (PHPS) and polycarbosilane hydroxyde (PCS-OH) were chemically modified with alkylamino silane derivatives, to afford amino-functionalized hybrid materials through PDC route, for the selective transport of CO2. The chemical modifications of the silicon-based preceramic polymers were studied using FT-IR and NMR. The chemically modified PHPSs were successfully converted into the amino-functionalized hybrid silica by room temperature oxidation, while the as-synthesized hybrids having PCS-OH matrix were purified by removing the excess amount of alkylamino silanes remained after the chemical modifications. The intrinsic micro-/mesoporous properties of the synthesized hybrids were characterized using N2 and Ar sorption. The CO2 uptake by the hybrids was investigated at the molecular level using thermogravimetric analysis under CO2 atmosphere, in-situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS), and CO2 sorption isotherm. The CO2 uptake mechanism involved chemisorption at very low partial pressures and physisorption at higher partial pressures, was demonstrated by the temperature dependence of the CO2 isotherms. The effect of the alkylamino silane functionalization in the hybrid samples with regard to non-functionalized samples, as well as the influence of adsorbed water within the hydrophilic PHPS-derived amorphous silica and the more hydrophobic PCS-OH matrix, highlighted by the difference in chemical reactivity of primary and secondary amino groups, will be discussed from a viewpoint to develop novel single source preceramic polymer-derived CO2-selective inorganic-organic hybrid membranes, with facilitated transport mechanism.