While it is possible to do things with jQuery in a React application, it's not necessarily a good idea. This is because you're operating with two competing paradigms. React maps the DOM into a virtual DOM, and relies on that DOM to not change in order to maintain sanity. jQuery jumps directly over React and manipulates the DOM itself. This results in a situation where React's virtual DOM is out of sync with the real DOM.
There are ways to use the two together, but it takes some effort.
I'd look at how Stardust uses React in place to jQuery to do things in semantic like handle dropdowns and modals.