Strategies for the production of substituted isoquinoline libraries were developed and explored. Routes involving microwave-assisted variants of the Bischler-Napieralski or Pictet-Spengler reaction allowed for cyclization of substituted beta-arylethylamine derivatives. The dihydroisoquinolines and tetrahydroisoquinolines thus generated could then be oxidized to their corresponding isoquinoline analogues. An alternate strategy, however, involving the preparation and activation of isoquinolin-1(2H)-ones is demonstrated to be a more practical, rapid, and efficient route to C1- and C4-substituted isoquinoline libraries.