Abstract New 6-chloro-and 6, 7-dichloro-4-(4-aminophenyl)-2-(N-alkylcarbamoyl)-1, 2- dihydrophthalazines (12, 18) were synthesized starting from 6-chloro-and 6, 7-dichloro-4-(4- nitrophenyl) phthalazine (8). Routes to 1-unsubstituted (12) and 1-methyl (18) derivatives are different. Key intermediates 8 were prepared from 4-chloro-and 3, 4-dichlorotoluene via ortho-formylbenzophenone derivatives 7.