Abstract: The invention relates to new quinoline derivatives of the general Formula I ##STR1## (wherein X stands for hydrogen, halogen or lower alkoxy;n is an integer of 1, 2 or 3;R.sup.1 represents hydrogen andR.sup.2 represents hydroxy-lower alkyl or lower alkoxy-lower alkyl or a group of the general formula IV, ##STR2## wherein Z stands for --O--, --S--, --NH-- or --N(lower alkyl)--; the dotted lines represent optional bonds; andm is 0 or 1; orR.sup.1 and R.sup.2 together with the adjacent nitrogen atom, they are attached to, form a 5- or 6-membered heterocyclic group which may optionally contain a further oxygen, nitrogen or sulfur heteroatom and may be optionally substituted),and pharmaceutically acceptable acid addition salts thereof. The new compounds of the present invention exhibit radiosensitizing effect, make hypoxial cells highly sensitive towards radiation and may be used in radiation therapy.