I am always stumped for where to eat in the Loop before or after the opera. That is why I have been waiting impatiently for the
Pearl Tavern to open at 180 N. Wacker (about 3 blocks from the Cadillac Palace Theater), and it finally has! Looks like a very attractive place with reasonable prices (and I do love oysters!). Alas, the Pearl Tavern won't work if your vegetarian boundaries exclude fish and shellfish, because those are almost all they have on the menu. You'd have somewhat better luck at
Catch 35 (35 W. Wacker), which has several salads, vegetable sides, and a couple of vegetarian main dishes on the menu. All my other pushpins for the Loop are more casual spots (e.g.,
Monk's Pub--lots of beers, not a lot of vegetarian options).
Looks like you may have better luck looking along the Brown Line back toward home. How about
Glen's Diner? Lots of craft beers and BYOB and some vegetarian options, and right at the Montrose stop on the Brown Line. Ah, but they close at 10.
"Your swimming suit matches your eyes, you hold your nose before diving, loving you has made me bananas!"