Family Celebration with Good Chow
this will be a U Chicago graduation meal with elderly grandparents in attendance. That means non-noisy, not too spicy or exotic (unfortunately), and not the very top end dressy expense account places either. Who's doing some really delicious cooking in town that might fit this bill?
North Pond, in Lincoln Park (the park itself, as opposed to the neighborhood called Lincoln Park), has a beautiful setting, is quiet, and features local, seasonal produce. But check out the menu to see if the ingredient combinations would push the limits of "exotic" for your party.
Custom House in the South Loop might be a safer choice in terms of pleasing diners with varied tastes:
The two places above have entrees in the $30+ range. A couple of places which are a step down in price (and fancy-ness) are, first, Timo, which recently changed its name from Thyme and changed its focus to be more Italian:
The walled patio in the back of Timo is lovely, perhaps the weather on your night in June would co-operate for al fresco dining.
Another possibility might be West Town Tavern (which is not a tavern!), a neighborhood spot producing really excellent food, mostly American.
Hope this helps get you started. We'd love to hear where you end up.