Blend ½ cup sugar and ½ cup filtered water in a blender until sugar is completely dissolved. Pour into a resealable jar, add one 3” cinnamon stick, and let sit at room temperature for at least 6 hours and up to 12 hours, until desired cinnamon flavor is reached. Remove cinnamon stick; chill until ready to use. Do Ahead: Syrup can be made 2 weeks ahead. Keep chilled.
Add 1 oz. bourbon, 1 oz. mezcal, ¾ oz. fresh lime juice, ¾ oz. fresh pineapple juice, and ½ oz. Cinnamon Syrup to a shaker tin with ice. Shake for 10–15 seconds. Strain into a cocktail glass.
