Who led people into mexican state of texas under the idea of increasing trade and improving the land with american settlers?

The correct answer is Stephen Fuller Austin.

Stephen was referred to as the father of Texas and also founder of Texas. He successfully colonized the region where he brought 300 families to the region from United States.

Before he moved to Arkansas he served Missouri Territorial legislature. He advocated conciliation where the settlers of Texas were being dissatisfied with government of Mexican.

Texas revolution was being escalated in Mexico. He also led the forces of Texas at Siege of Bexar before serving in United States as a commissioner which was successful.