Synthesis and crystal structures of 7-bromo-5-(2′-chloro)phenyl-3-hydroxy-1-methyl-1,2-dihydro-3H-1,4-benzodiazepin-2-one and 7-bromo-5-(2′-chloro)phenyl-1-hexyl-1,2,4,5-tetrahydro-3H-1,4-benzodiazepin-2,3-dione

► Synthesis and structural study of benzodiazepin-2-one derivatives. ► Influence of substituent in position 1 on heterocycle conformation and distortion. ► Proton migration. ► Contribution of H-bonds and halogen bond interaction to the overall structure organization and heterocycle distortion.