The present invention provides novel tricyclic 1, 4-benzodiazepinone derivatives of the general formula (I) and pharmaceutical compositions containing them. Moreover, the compounds of formula (I) and the pharmaceutical compositions containing them are provided for use in the treatment and/or prophylaxis of conditions associated with altered glutamatergic signalling and/or functions, and/or conditions which can be affected by alteration of glutamate level or signalling in mammals. The tricyclic 1, 4-benzodiazepinone derivatives of formula (I) can act as modulators of nervous system receptors sensitive to glutamate, in particular as modulators of metabotropic glutamate receptors (mGluRs), which makes them particularly suitable for the treatment and/or prophylaxis of acute and chronic neurological and/or psychiatric disorders. The present invention further provides tricyclic 1, 4-benzodiazepinone derivatives of formula (I) that are modulators of metabotropic glutamate receptors (mGluRs), particularly positive allosteric modulators of mGluRs, and more specifically positive allosteric modulators of mGluR3. (I)