Trim fat from chops. Place chops in a plastic bag set in a shallow dish.
For marinade, in a small bowl combine brown sugar, oil, orange juice, cilantro, vinegar, chili powder, cumin, oregano, salt, red pepper (if desired), cinnamon, and garlic.
Pour over chops; seal bag. Marinate in the refrigerator for 2 to 24 hours, turning occasionally.
Drain chops, discarding marinade. For a charcoal grill, grill chops on the rack of an uncovered grill directly over medium coals for 12 to 15 minutes or until chops are done (160°F), turning once halfway through grilling. (For a gas grill, preheat grill. Reduce heat to medium. Place chops on grill rack over heat. Cover and grill as above.)