Combine granulated sugar and water in small saucepan over medium heat. Heat until sugar is dissolved.
Add fresh blueberries and simmer for 5 minutes, until blueberries are breaking down.
Pour blueberries mixture through a strainer into a small bowl; pressing to release all liquid. Let cool to room temperature.
To Make Lemonade
Combine thawed lemonade concentrate and cold water and stir thoroughly.
Refrigerate to chill.
To Make Cocktail
Pour a little blueberry simple syrup in the bottom of serving glass, top with ice, pour in lemonade to 3/4 full and top off glass with club soda. Gently stir.
Garnish with fresh blueberries, lemon slices, and mint sprigs.