Butter bottom and sides of 8-inch square pan.
In 3-quart saucepan, heat corn syrup and brown sugar to boiling over medium-high heat, stirring constantly. Remove from heat. In small bowl, stir coffee granules into boiling water until dissolved; stir into corn syrup mixture along with peanut butter until smooth. Add cereal and pretzels, stirring until evenly coated.
Press evenly in pan. Let stand about 2 hours or until set. For bars, cut into 4 rows by 3 rows. Store covered.