Besides both being well-known pain relievers? They were both synthesized by the same man, Felix Hoffmann, in August of 1897. Wired has an article.

Bayer AG still holds the rights to the trade name aspirin in more than 80 countries. Elsewhere, as in the United States, the word is often used generically to refer to almost any brand of acetylsalicylic acid and even other over-the-counter pain relievers. Legal maneuvering aside, Hoffmann’s wonder drug was a gold mine. Bayer certainly cleaned up, seeing as how it held a monopoly on aspirin through the end of the First World War. Following Germany’s defeat, Bayer was forced to sell off its U.S. production plants as part of war reparations.

Tip o’ the hat to Mind Hacks for putting me on to this item.