Megasthenes was succeeded as ambassador by

Megasthenes was born in Asia Minor and became an ambassador of Seleucus I Nicator of the Seleucid dynasty to Chandragupta Maurya in Pataliputra, India. ... Other Greek envoys to the Indian court are known after Megasthenes: Deimachus as ambassador to Bindusara, and Dionysius, as ambassador to Ashoka.