Conger connected on two free throws with 30.8 seconds remaining to break a 75-75 tie and the senior drained three more from the foul line after a Michael Davenport steal in the final seconds to secure the win for the Bonnies (3-1).
Conger turned in a solid all-around performance with 18 points, 10 rebounds and five assists for SBU, which also received 12 points and a career-best 12 rebounds from Simmons. Chris Johnson tied his career-high with 19 points and Eric Mosley also reached double figures in scoring with 11 points for the Bonnies.
Bona led by as many as eight points in the second half and never trailed after a 3-pointer by Johnson tied the score at 35 with 18:59 remaining. But Niagara (2-3) twice rallied to tie the game in the final minutes, as Antione Mason's 3-pointer with 58 seconds to play knotted the score at 75.
St. Bonaventure regained the lead on free throws after Conger was fouled going for an offensive rebound. Davenport then stripped Niagara's T.J. Cline in the post with six seconds remaining and Conger canned 3 of 4 free throws following a personal foul on Marvin Jordan and technical foul assessed to the Purple Eagles' bench.
The Bonnies trailed at the half for the first time this season, but they took control in the second half with the help of hot perimeter shooting and rugged rebounding. Bona made seven of its 14 3-point attempts after halftime and out-rebounded Niagara 43-36 for the game.
Johnson drained a pair of 3-pointers early in the second half to ignite the Bonnies, who had fallen behind by seven points during the first 20 minutes. A 10-2 run that included 3-pointers from Mosley and Conger gave SBU a 56-48 cushion with 10:25 remaining. The Bonnies led 67-60 after a Simmons lay-up and 73-67 on a Johnson jumper with three minutes left.
Johnson and Mosley each drilled 3-of-6 3-pointers for Bonaventure, which was 10-for-23 from long range as a team. The Bonnies also capitalized on their free throw attempts, going 18-of-21. Conger was 9-for-10 on free throws.
Simmons' aggressiveness on the glass helped him collect seven offensive rebounds and Bona had 18 offensive boards as a team, which led to extra trips to the foul line. Simmons logged his first career double-double, while Conger recorded his ninth career double-double and first since going for 22 points and 10 rebounds against Massachusetts in last season's Atlantic 10 Tournament semifinals.
Mason netted 19 points and Ameen Tanksley had 16 to help Niagara stay close. The Purple Eagles took a 12-11 lead on two Tanksley free throws midway through the first half and didn't trail again until the early minutes of the second half. Niagara scored seven straight points to gain a 25-18 lead, its largest of the first half, and led 33-32 at intermission.
The Bonnies continue their non-conference schedule at Ohio at 7 p.m. Wednesday.