Hi there Realrealtor :)
This is your first itme coming to Chi-Town. Our city is amazing and we have a lot to offer! I'll try to give helpful suggestions.
Restaurants: I would suggest The Green Zebra, a vegetarian restaurant with a nice menu. You may want to google them and look at their menu ahead of time. Also, I suggest if you do go to make reservations.
If you also like some good hearty food. I strongly suggest you try our Chicago style pizza. There's nothing like it! Gino's East (which I actually ate today) is one of the best in the city with an amazing deep dish pizza.
For some Jazz, you may want to check out Artis's Lounge. As you probably know, there are a ton of Jazz lounge's within the city. You may want to look google Chicago Jazz lounge's, and see what others look good. I personally, don't go to these lounge's, so I'm not the best person to ask. But, I've heard Artis's is among the best.
I'm a fellow opera lover myself. Unfortunately, The Lyric Opera house does not have performances until this fall. Also, to go to the opera house, requires tickets purchased months in advance. If you are to return to Chicago, I suggest to go ahead and check out the future opera's at Lyric. The tickets are incredibly expensive and sell like hotcakes. I have to wait until Novemeber to see the opera I've been waiting for.
Also, if you'd like some other suggestions:
The Chicago Art Institute is an amazing museum, where you can spend hours pindering classic pieces.
The Lincoln Park Zoo (which I actually went to today) is among the oldest zoo's in the country. It is also said to be one of the best zoo's worldwide (which i agree with.) Plus, admission is totally free!
The Shedd Aquarium is the world's largest indoor aquarium, with over 8,000 sea creatures. You really don't want to miss out going to the Shedd.
Navy Pier is an amazing place with tons of stores, and retaurants, activities, and a whole lot more to see.
You may also want to check out the amazing Sears tower, and John Hancock buliding.
I really hope I was able to help you. Do you have any more questions? Enjoy our city and have fun! If you'd like to know anything else, feel free to ask. I hope you have an enjoyable visit in our beautiful city! :)