Coincidence is often confused with irony.
As far as I understand it, irony is laced with a historical foundation whether in the context of a story or simply in the sense of history behind a given outcome, as indicated in the images below (though they would probably have more impact without the explanatory notes underneath).
It is an awareness of the history and its outcome that reveals the irony and in so doing yields a higher truth.
Who says irony has to be tragic?
Is it ironic that clowns are scary?
Picked this t-shirt up at a Goodwill.
Ironic, don't you think?