Anxiolytic-like effects induced on mice by several compounds with imidazo[2,1-a]isoindolol (II), pyrimido[2,1-a]isoindolol (III) and [1,3]diazepino[2,1-a]isoindolol (IV) structures have been evaluated through the elevated plus-maze test. The evaluation has been based on measuring the spent time and counting the number of entries of mice in the open arms of the maze. Single intraperitoneal administration of imidazoisoindolol IIe and pyrimidoisoindolols IIIa, IIIe and IIIg induced significant increments in these behavioural parameters.