Milan, who host AS Roma next weekend in their final game before the winter break, are guaranteed to finish the year at least joint-top and with almost half the season gone, they look big favourites for a first scudetto since 2004.
The easy victory also meant Milan moved 13 points ahead of faltering champions Inter Milan [ Images ], who are not playing this weekend because of their involvement in the Club World Cup.
The Rossoneri, who had already qualified for the last 16, suffered a wobble in Wednesday's home Champions League [ Images ] defeat by Ajax Amsterdam but Zlatan Ibrahimovic [ Images ] returned to the team in place of Ronaldinho [ Images ] at Bologna and his extra spark was key.
The goals again showed how Milan coach Massimiliano Allegri, a virtual unknown outside Italy [ Images ] when appointed in the close season, has improved the style of play compared to Leonardo last term and the latter years of Carlo Ancelotti's [ Images ] reign.
Speed and directness are now of the essence rather than the patient but often ineffective build-up play of the past.
Ibrahimovic's cross allowed Ghana midfielder Boateng to grab the opener on nine minutes before the former Portsmouth player, who made little impact in the Premier League, produced a wonderful flick to release Robinho to score after 35 minutes.
Ibrahimovic then chested down and finished off Andrea Pirlo's pass in the second half, meaning Milan's three main close-season signings all scored again for the second straight league game following last weekend's 3-0 win over Brescia.
Bologna, who won their last two matches, missed a penalty late on when Christian Abbiati saved Marco Di Vaio's effort.
Bologna's players have not been paid for weeks and the club has been put up for sale with the first team able to walk out for free in January if wages are still not forthcoming.
A group of local businessmen including the owner of coffee company Segafredo are interested and a deal could come soon.