This was the first study to apply cyclodextrin glucanotransferases (CGTase, EC 2.4.1.19) produced by mesophilic, thermophilic, alkaliphilic, and halophilic bacilli as well as pullulanase, beta-amylase, beta-galactosidase, and beta-fructofuranosidase for transglycosylation of benzo[h]quinazolines. The combination of CGTase produced by Bacillus stearothermophilus ST-88 and gamma-cyclodextrin (CD) used as a donor of glucosyl residues was the most efficient. The derivatives obtained are water-soluble. The synthesized products have been purified by various chromatographic methods and their fine structures have been determined.