Alberto Gilardino put the hosts ahead in the 20th minute before Alessio Cerci doubled the Viola's advantage two minutes after the restart.
Fiorentina coach Sinisa Mihajlovic had demanded his players' full concentration against Bologna after his team's dismal start to the last campaign.
The Florence outfit mustered just one win from their opening seven Serie A fixtures last term.
The Viola dominated possession and went ahead in the 20th minute.
Gilardino got his head on Manuel Pasqual's cross and his powerful effort from the heart of the area beat Bologna goalkeeper Jean Francois Gillet.
Bologna almost equalised on the half-hour mark.
Alessandro Diamanti fed Nico Pulzetti and his right-foot strike from 10 yards was kept out by Fiorentina goalkeeper Artur Boruc.
The visitors could have pulled level before half-time but Diamanti's bullet strike from 30 yards went just wide of the far post.
Fiorentina doubled their lead early in the second half.
Stevan Jovetic fed Cerci inside the area and he fired past Gillet.
The visitors should have reduced the arrears in the 77th minute but Diamanti's left-footed shot from 25 yards rebounded off the far post with Boruc already beaten.
At the other end, an unmarked Cerci wasted a good opportunity as he fired wide from a good position.
Fiorentina kept going forward and almost made it 3-0 with one minute left to play.
Jovetic got past his marker and his right-footed strike from outside the area went just wide of the far post.