Provided is a process for producing highly pure 4-amino-1-isobutyl-1H-imidazo[4,5-c]quinoline (imiquimod), which includes reacting 4-chloro-1-isobutyl-1H-imidazo[4,5-c]quinoline with a non-gaseous amine precursor. Also provided are methods for isolating highly pure imiquimod. Further provided are intermediates useful in the production of imiquimod, methods for producing such intermediates, and methods for obtaining imiquimod from such intermediates.