Light grill charcoal and get to medium heat (can hold hand over coals 4-5 seconds).
While grill heats, prepare chops and sauce.
Combine coriander, paprika, cumin, 1 Tbsp salt, 3 Tbsp black pepper, and 1 Tbsp brown sugar in small bowl; mix well. Rub the pork chops generously on both sides with the spice rub. Set the chops aside while making the sauce.
In large skillet over medium heat, heat oil until hot. Add onion; cook, stirring occasionally, until golden brown, about 11 to 13 minutes. Add peaches, ginger and tomatoes; cook, stirring frequently for 2 minutes. Stir in vinegar, orange juice, remaining 1/3 cup brown sugar, allspice and salt and pepper to taste. Bring to a boil, then reduce the heat and simmer until the mixture is reduced by about half and thickened slightly, about 20 minutes.
Taste the sauce and adjust the seasonings, then transfer the sauce to a blender or food processor and puree until smooth. Reserve 1/4 cup sauce for basting the chops; pour the remaining sauce into a small serving bowl.
Cook the chops on the grill, turning once, until they reach the desired doneness, 8 to 10 minutes a side, baste the chops generously with sauce.
Serve the chops hot with extra barbecue sauce on the side.