In the container of a blender, combine chopped pineapple, brown sugar, soy sauce, green onion, garlic, ginger, Sriracha, cumin, and coriander; process until smooth.
In a large bowl, add chicken. Pour pineapple mixture over chicken and toss to coat. Cover and refrigerate up to 2 hours.
Remove chicken from marinade and pat dry; reserve marinade. Season chicken with salt and pepper.
In a small saucepan, stir together reserved marinade, ketchup, and vinegar. Cook until sauce is bubbly and thick, 8 to 10 minutes. Remove from heat.
Heat a large grill pan over medium heat. Add chicken; cook, turning occasionally to prevent burning, until grill marks form. Brush with marinade and cook until caramelized and an instant-read thermometer inserted into thickest part of chicken registers 165°, 20 to 30 minutes. Add pineapple slices to grill pan; cook until tender. Cut pineapple into quarters.
Serve chicken with pineapple and sauce.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/pineapple-chicken-thighs-recipe/