In a stockpot, over medium heat, cook the oil, garlic, onion, and green pepper until slightly softened, stirring occasionally, about 5 minutes.
Add the tomatoes, chickpeas, kidney beans, vegetable broth, cumin, and salt. Bring to a boil over high heat.
Reduce heat to low, cover, and simmer, stirring occasionally, until thickened, 1 to 1 1/2 hours.
Before serving, stir in the chocolate until melted.