The Collaborative International Dictionary of English v.0.48:

Dipyridine \Di*pyr"i*dine\ (?; 104), n. [Pref. di- + pyridine.]
   (Geom.)
   A polymeric form of pyridine, C10H10N2, obtained as a
   colorless oil by the action of sodium on pyridine.
   [1913 Webster]