Access bank and diamond bank new name

You're referring to the recent rebranding of Access Bank and Diamond Bank in Nigeria!

As of 2018, Diamond Bank merged with Access Bank, and the resulting entity was rebranded as Access Bank. The merger was completed in April 2018, and Diamond Bank's operations were fully integrated into Access Bank.

So, to answer your question:

The rebranding was aimed at creating a stronger, more competitive bank in the Nigerian market, with a broader customer base and a wider range of products and services.