A bulk polyimide system prepared by pressing of the precursor monomers 4,4'-oxidianiline (ODA) and 1,2,4,5-benzenetetracarboxylic or pyromellitic dianhydride (PMDA) mixtures has been investigated. The synthesized bulk polyimide is formed as a result of a polycondensation reaction of monomers in solid state phase. A change of the monomers polycrystalline structure to an amorphous one of the bulk polyimide after imidization is established The possibility for excimer laser microstructuring by drilling at various diameters and depths is demonstrated. The scanning electron microscopic observations reveal alterations in the so formed blind holes as a consequence of thr laser action parameters variation. The changes observed and the dependencies obtained are discussed.