The Wildcats (3-0) will face Alabama in Friday night's championship game. The Crimson Tide beat Oregon State 65-62.
The Boilermakers (1-2) missed 12 of their 28 free throws and shot just 5 of 23 from beyond the arc.
D.J. Byrd led Purdue with 16 points, and also added five assists and as many rebounds.
Terone Johnson scored 13 points and dished out four assists, while Ronnie Johnson added 12 points and nine assists.
Donnie Hale pulled down a team-best six boards to go with 11 points, while Rapheal Davis scored four points on 1 of 4 shooting.
Purdue will play Oregon State today at 5 p.m. (ESPNU).
Darrun Hilliard set his career high for the second straight game, finishing with 22 points for Villanova. Freshman Ryan Arcidiacono had 18 points for the Wildcats and Bell added 16.
Bell hit his first 3 to break the 75-all tie and his second made it 83-79 with 2 minutes left. That started a 9-0 run that gave the Wildcats the win in Madison Square Garden.