Which city in the Sahel became a cultural and economic center

Timbuktu

Explanation:

It became part of the Mali Empire early in the 14th century. In the first half of the 15th century, the Tuareg tribes took control of the city for a short period until the expanding Songhai Empire absorbed the city in 1468. A Moroccan army defeated the Songhai in 1591 and made Timbuktu, rather than Gao, their capital.