3-Chloro-1-methyl-6-(p- methylphenoxy ) benzo [c][1,8] naphthyridine has been prepared, the reactions with various nitrogen, oxygen and sulfur nucleophiles studied, and the results compared with those for the 1- chloro-3-methyl isomer. The 6-position was more reactive for oxygen and nitrogen nucleophiles, so much so that an initially added 6-NHR group was displaced by a second R′NH2 nucleophile at least as readily as was the 3-chloro group. With p- chloro ( thiophenol ), however, the 3-chloro group was preferentially displaced.