Preheat oven to indirect medium-high heat.
Generously season the chicken thighs with the Cajun seasoning.
Sea salt and freshly ground black pepper, 2 tbsp. Cajun seasoning
Place the blueberries, orange juice, chill powder, and cinnamon in a blender. Pulse until smooth.
2 cups fresh blueberries, ½ cup orange juice, 1 tbsp. chili powder, 1 tbsp. ground cinnamon
Pour in the BBQ sauce and season to taste; pulse again until well blended. (If the sauce is too thick, add more orange juice or water)
1 cup homemade BBQ sauce, Sea salt and freshly ground black pepper
Refrigerate the sauce until ready to use.
Grill the chicken thighs over direct heat until browned on both sides, 2 to 3 minutes per side.
6 to 8 chicken thighs
Transfer to indirect heat, cover, and cook for 30 to 35 minutes.
Baste the chicken generously with the BBQ blueberry sauce, and grill over direct heat until the sauce caramelizes.
Let the chicken rest for 4 to 5 minutes before serving.