Abstract A series of new l-phenyl-4 (1H)-quinazolinones and 2, 3-dihydro-1-phenyl-4 (1H)- quinazolinones were synthesized and tested as cholecystokinin receptor ligands. All the compounds showed moderate affinity and 1-phenyl-4 (1H)-quinazolinones resulted more effective towards the cholecystokinin-B receptor, meanwhile the dihydro derivatives were generally more effective towards the cholecystokinin-A receptor.