Imidazoquinazoline derivatives have biological activities in different aspects. Therefore, they are applied as active substances in drug production. Moreover, their physical properties, for example, high decomposition temperature ~400 degree of Celsius make them useful in thermally stable polymers production.My research with molecular modeling methods confirms the structure of imidazoquinazolinodione derivatives and explain the course of the synthesis reaction. Modeling the entire space of solutions, i.e. products of reaction of 1-phenyl-2H,6H-imidazo-[1,5-c]quinazolino-3,5-dione with sequencing moles of ethylene oxide together with appropriate transition states, allowed to clearly define and explain the directions of subsequent reactions. The used methods indicate that molecular modeling, often treated as purely theoretical, finds practical application and can sometimes be the only tool to explain the obtained experimental results.