The present invention relates to novel substituted quinoline derivatives according to the general Formula (Ia) or the general Formula (Ib) the pharmaceutically acceptable acid or base addition salts thereof, the stereochemically isomeric forms thereof, the tautomeric forms thereof and the N-oxide forms thereof. The claimed compounds are useful for the treatment of mycobacterial diseases, particularly those diseases caused by pathogenic mycobacteria such as Mycobacterium tuberculosis, M. bovis, M. avium and M. marinum. In particular, compounds are claimed in which, independently from each other, R1 is bromo, p=1, R2 is alkyloxy, R3 is optionally substituted naphthyl or phenyl, q=1, R4 and R5 each independently are hydrogen, methyl or ethyl, R6 is hydrogen, r is equal to 0 or 1 and R7 is hydrogen. Also claimed is a composition comprising a pharmaceutically acceptable carrier and, as active ingredient, a therapeutically effective amount of the claimed compounds, the use of the claimed compounds or compositions for the manufacture of a medicament for the treatment of mycobacterial diseases and a process for preparing the claimed compounds.