Abstract A method for synthesizing o-carborane substituted tetrahydroisoquinolines containing a polar functional group such as sulfonic or phosphoric acid on the nitrogen atom of the piperidine ring, starting from N-(2-arylethyl) sulfamic acid or 2- arylethylamidophosphate, is described. In vitro studies showed that the desired compounds 7a and 10b accumulate to high levels in B-16 melanoma cells despite low cytotoxicity.