The dissertation concerns the search of new anticonvulsant active compounds in a group of N-phenyl- amino derivatives of 1,3-substituted pyrrolidine-2,5- diones. The introduction chapter describes the essential role of heterocyclic imide and lactam moieties in relation to the biological activity of central nervous system agents. In the experimental section the synthesis of 59 new N-phenylamino-pyrrolidine-1,3-diones has been described. The structural modifications concerned position 1 and 3 of succinimide ring. The aim of work was the evaluation of the structure – activity relationships in this group of derivatives. The in vivo studies for anticonvulsant activity were performed within the Anti- epileptic Drug Development (ADD) program in Epilepsy Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, USA. The results obtained revealed that majority of compounds showed protection in the electrical or/and metrazole seizures. These animal models are the most frequently used tests that enable identification of anticonvulsant active substances. For all compounds the lipophilicity was determined by use of the chromatographic methods. The results enabled assessment of correlation between the lipohpilicity and anticonvulsant activity. In addition for chosen molecules their stability in acid as well as basic environment was examined. In ; conclusion, the aim of dissertation has been accomplished and the results obtained justified the further investigation in a group of 1,3-substituted pyrrolidine-2,5-diones as potential anti- convulsant agents.