Rolando Bianchi squandered the game's best chance when he won the spot-kick two minutes after half-time but saw it saved by home goalkeeper Rafael.
And relegation-threatened Bologna's frustration at letting the chance of maximum points elude them spilled over late on when first-half substitute Jonathan Cristaldo was dismissed for an elbow on Vangelis Moras.
Bianchi and Rafael went head to head for the first time 12 minutes in when the striker beat the offside trap and shot for the bottom corner. The Brazilian goalkeeper got down well to save.
At the other end, Juan Iturbe's cross was headed goalwards by Bosko Jankovic but goalkeeper Gianluca Curci emulated his opposite number.
Rafael saved from Lazaros Christodoulopoulos and Bianchi shot high over the bar while Verona's only other chance of the first half also fell to Jankovic, who shot wide.
Bologna, needing to make the most of chances to lift themselves further clear of the bottom three, should have been ahead early in the second period when Bianchi was pushed in the area by Moras, but Rafael dived to his left to save.
Christodoulopoulos worked a shooting chance on the hour but fired high and wide, and seventh-placed Verona took the upper hand thereafter.
Jankovic shot over and midfielder Romulo was denied by Curci in the last of the goalmouth action - but there was still drama to come.
Cristaldo, a 33rd-minute replacement for the injured Panagiotis Kone, was booked along with Moras in the 81st minute and, as the pair continued to jostle, Kone swung an elbow at the Greece and former Bologna defender a minute later and was sent on his way.