The capital city of Tamil Nadu is:

The capital city of Tamil Nadu is Chennai. It is the most populous city in the state and the fourth most populous city in India. Chennai is a major economic and cultural center in India. It is home to many industries, including information technology, automobile manufacturing, and textiles. Chennai is also a major tourist destination, with many historical and cultural attractions.

Madurai is the second largest city in Tamil Nadu and is known for its temples and palaces. Coimbatore is the third largest city in Tamil Nadu and is a major industrial center. Trichy is the fourth largest city in Tamil Nadu and is known for its temples and forts.