Highly substituted isoquinolines have been synthesized by two different pathways using either a Pictet-Grams or a Bischler-Napieralski approach. While the first synthesis afforded C1-functionalizable 1,3-dimethylisoquinoline derivatives, the second approach allowed the isolation of isoquinoline derivatives bearing a reactive ester function at the challenging C3 position. Among the large variety of efficient chemistry that can be independently or simultaneously performed at the C1 and C3 positions of the isoquinoline ring, 1,3-dibromomethylisoquinoline derivatives have proven to be efficient intermediates for the synthesis of highly valuable ligands for lanthanide complexation.