No, if you focus on optimizing for Google, you'll do great in Bing/Yahoo. From my data, Bing/Yahoo traffic is horrible and doesn't convert near as well as G traffic.
You don't need to especially focus on Bing. Microsoft Bing is the second largest search engine but is still far away from Google. I share only 2.83%. If you write any SEO-optimized article for Google then it will work fine for every search engine.