Mercantile Bank, long an unsung leader in banking technology, is about to get a bigger platform for innovation.

It was announced today that  Mercantile Bank Corp. and Firstbank Corp. would merge and form the third largest bank in Michigan.

The combined bank will use the Mercantile name and will hold assets totaling $2.8 billion, loans of $2.0 billion and deposits of $2.4 billion. The new bank will field 53 branches to serve the combined customer base.

MercBank’s strengths are in technology (covered numerous times on Bank Innovation) and commercial lending, while Firstbank has a strong branch network.

Mercantile Bank was the first bank to partner with PayPal for person-to-person payments and bill.com for bill pay. Additionally, the bank has an innovative social media program involving custom videos and contests in the community, and has made creative efforts to reach younger customers in a university setting using a microbranch and video banking — as well as marketing to their parents.

After the merger, MercBank shareholders will won approximately 52% of the stock in the combined company, and Firstbank shareholders 48%.