Imidazo ring compounds (e.g., imidazoquinolines, 6,7,8,9-tetrahydroimidazoquinolines, imidazonaphthyridines, and 6,7,8,9-tetrahydroimidazonaphthyridines) with a sulfide-, sulfinyl-, or sulfonyl-containing ether substituent at the 1-position, pharmaceutical compositions containing the compounds, intermediates, methods of making the compounds, and methods of use of these compounds as immunomodulators, for inducing cytokine biosynthesis in animals and in the treatment of diseases including viral and neoplastic diseases, are disclosed.