The genesis of the adsorptive structure of carbogenic molecular sieves (CMS) derived from poly(furfuryl alcohol) (PFA) was investigated as a function of the synthesis temperature (from 400 to 1200-degrees-C) and soak time (from 0 to 8 h). The apparent CO2 adsorption capacity of these materials maximizes at 93 mg/g with a final synthesis temperature of 800-degrees-C. The maximum adsorption capacity is obtained from the 24-h CO2 uptake of 93 mg/g at a relative pressure of 0.015 and at T = 295 K. C-13 CP-MAS NMR spectra of the carbon produced at lower synthesis temperature and short soak times shows a resonance that is reminiscent of the PFA precursor. At higher synthesis temperatures and longer soak times, the NMR spectra display resonances attributable only to aromatic microdomains.