The Collaborative International Dictionary of English v.0.48:

Thionol \Thi"on*ol\, n. [Thionine + -ol.] (Chem.)
   A red or violet dyestuff having a greenish metallic luster.
   It is produced artificially, by the chemical dehydration of
   thionine, as a brown amorphous powder.
   [1913 Webster]