The acylation courses of 5-bromo and 5,7-dibromo derivatives of benzoxazolin-2--one (BO) and isomeric 3-hydroxy-1,2-benzisoxazoles (BIO) with acetic anhydride, benzoyl chlorides and alkyl chloroformates were investigated. In view of principal course of N-acylation in BO-and O-acylation in BIO-group some of the newly obtained compounds, namely 5,7-Br2-2-(o-chlorobenzoyloxy)-BO (5a) and N-alkoxycarbonyl BIO (22a--27a) make the exceptions. Compounds 25a and 26a were found to possess relatively the most intensive depressant action on the CNS.