This invention relates to novel thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepines, and pharmaceutically acceptable salts thereof. This invention also provides compositions comprising a compound of this invention and the use of such compositions in methods of treating diseases and conditions that are beneficially treated by administering an inhibitor of binding between an acetylated histone and a bromodomain-containing protein.