The Mariners won for the third time in four games, getting a six-inning effort from Aaron Harang and three innings of no-hit work from the bull pen.
Franklin hit a two-run homer in the first inning and Saunders had a solo shot in the second along with a sacrifice fly in the fourth.
That gave the Mariners a 4-0 lead and Harang (4-7) held off the Reds until the relief corps could take over. Harang gave up two runs, one of them a solo homer by Joey Votto in the sixth, on six hits with one walk.
Oliver Perez completed the work of the relief corps by striking out the side for his second save.
Cincinnati starter Mike Leake (7-4) allowed four runs on five hits in five innings to take the loss.