Ochanomizu Saint-Clair is a 21-story high-rise building primarily used for offices, with shops and cafes on the B1F and 1F.
To get to Ochanomizu Saint-Clair, you can access it directly from the Hijiri-bashi Exit of JR Ochanomizu Station, or from Exit B1 of Shin-Ochanomizu Station on the Tokyo Metro Chiyoda Line.
(Source: Ochanomizu Saint-Clair Official Floor Guide)
The above is the B1F floor map of Saint-Clair.
There's a place to sit and take a break at the "Sank Garden Plaza" in front of Excelsior and Burger King on the upper right!
There are about 10 metal tables that can seat 4 people each.
Although it is not explicitly stated that the tables are for the exclusive use of restaurants, it seems like a good idea to purchase something from Burger King or Excelsior and use them.
It's outdoors, so there is no shade or rain protection.
Since it is a table seat with good access from Ochanomizu Station, it is highly convenient.
In addition, there are indoor "Saint-Clair B1F sofa seats" nearby, so please consider them as well.
So, why not use it as a meeting place or a place to take a break around Shin-Ochanomizu Station?