Disclosed herein are potent and selective aryl-substituted heterocyclic compounds, useful as inhibitors of phosphodiesterase 4 (PDE4), compositions comprising the same, and their application as pharmaceuticals for the treatment of disease. Methods of inhibition of PDE4 activity are also provided, as well as methods for the treatment of inflammatory diseases and other diseases in which PDE4 or one of its isoforms may play a role.