DuPont to sell Chestnut Run labs to Pennsylvania developer after previous deal fell through Brandon Holveck, Delaware News Journal A look at the development projects in New Castle County Delaware Online/The News Journal is tracking entering 2021 Replay Video UP NEXT Months after a deal to sell its Chestnut Run laboratories off Route 141 fell through, DuPont has found a new buyer. The company intends to sell the Chestnut Run lab buildings and property – located within its campus headquarters – to Pennsylvania developer MRA Group. MRA Group announced the move Tuesday morning, saying it has signed a letter of intent for a deal it expects to close by the third quarter of 2021. It did not share the terms of the sale.