South Florida downtowns are on the cusp of growth that’s put them on the map as major urban centers — yet two big-name developers have opted to sit on their downtown properties.

Moishe Mana, the Israeli-born entrepreneur best known as being one of the Wynwood redevelopment pioneers, has invested more than $301 million buying about 51 properties in Miami’s Central Business District, but signs of his planned mixed-use project are yet to be seen. The exception is a recent announcement from his brokers that Mana’s looking for Blockchain or other tech companies to lease six floors of offices at 100 E. Flagler St.