The pore formation in the system resol resin - ethylene glycol - p-toluenesulfonyl chloride based on polymerization induced phase separation (PIPS), post-curing and pyrolysis techniques are studied by thermal analysis methods, pyrolysis gas chromatography mass spectrometry and electron microscopy. The presence of p-toluenesulfonyl chloride leads to accelerating of curing reaction and reaction order increasing. It was shown that PIPS step determines the texture and morphology of final carbon matrix precursors. The increasing of PIPS step temperature results in decreasing of the segregation scale and increasing of segregation intensity of phase separation. The decreasing of PIPS step temperature leads to increasing of macropores sizes, but decreasing of mesopores cumulative volumes. The increased mesopores content at high PIPS temperature is supposed to be resulted and from the oligoethylene glycol formation. Insufficient PIPS step time leads to partial collapsing of formed porous structure during pyrolysis.