Joey Graham added 19 points for the Raptors, who clinched their first Atlantic Division title last Friday and their first playoff spot in five years last month.
"This is a very big win for us," Bosh said. "It's a team that we could see in the playoffs. We just wanted to set the tone and show people that we are very serious about protecting this home court."
The Bulls had won seven straight at the Air Canada Centre. Toronto set a team record with its 28th home victory.
The Raptors have won eight of 10 to move within 1½ games of Chicago and Cleveland for the second-best record in the Eastern Conference.
"We've got confidence and we're going into home stretch here. The idea is to try to play the best basketball this time of year," Parker said.
Toronto is 31-15, the best record in the East, since Jan. 1.
Ben Gordon had 27 points for the Bulls, who lost for the second time in eight games.
"I definitely wouldn't understatement them going into the playoffs. They are a really good team," Gordon said. "They play with a lot of energy and it seems like everybody knows their role on the team. They just play off each other."
Andres Nocioni returned to Chicago's lineup after missing 28 games with plantar fasciitis. He had three points in eight minutes.
Toronto outscored Chicago 36-22 in the last 13:56.
Parker started it with a 3-pointer and Juan Dixon made a buzzer-beating 3-pointer at the end of the third quarter.
Parker's previous career high was 23 points on Jan 26. against Boston. His 3-pointer with 3:49 left gave Toronto a 101-82 lead.
"They are definitely a dangerous team, they do a good job of playing together," Chicago's Kirk Hinrich said. "I expect them to be very dangerous here in a couple of weeks."
Bosh -- a first-time All-Star starter this year -- has a double-double in eight straight games. He went 5-for-14 from the field, but 12-for-14 from the line.
Toronto went 9-for-19 from beyond the 3-point arc.
The Bulls led by four at halftime, but Toronto outscored Chicago 31-17 in the third quarter. The Raptors led by as many as 21 points.
"Once you start wining, winning breeds confidence and we are playing with a lot of confidence," Toronto coach Sam Mitchell said.
Toronto's Morris Peterson was ejected in the first half for knocking Hinrich to the floor. Peterson was slapped with a Type 2 flagrant foul, which means an automatic ejection.
He caught the Bulls guard on the face when he was airborne, sending him falling to the floor.
- The Raptors have been winning despite missing Andrea Bargnani (appendectomy) and Jorge Garbajosa (ankle). Bargnani hopes to return Friday.
- Graham tied a career high in points.