We talked to the 35-year-old, 16-3 (12 KO's) UFC star ... and asked him if he still had designs on hopping to the boxing ring.
"It's always been down the line. This is something I'm not taking my eyes off of. It's gonna happen, either way. Even if, when the UFC and I finalize a deal, the boxing part has to be into it because I can't see myself retire without boxing," Francis says.
FYI, Francis has 1 fight left on his deal with Dana White's organization ... a title defense against interim champ, Ciryl Gane.
But, Ngannou isn't looking to box a tomato can ... he literally is going straight to the top for an opponent.
"Tyson Fury, Deontay Wilder. I would like to test myself to that level," Francis told us.
"It's not the same sport, although I'm the champion, I'm in the top in this division. At the end of the day, it's just about like trained hands, trained punches, having a good delivery system to produce bombs and I'm sure that if I deliver my own punch, it's pretty good, I can make some damage."
Of course, Fury -- the top heavyweight boxer in the world -- recently beat fellow great Wilder in one of the best heavyweight fights of all time.
Fury is likely to fight Dillian Whyte early next year. Wilder's next move is currently unknown. But, a Ngannou fight vs. either man would obviously be a huge event.