A diet coke that is drank in a corporate environment for the purpose of improving efficiency. Business cokes must be consumed when wearing at least business casual, and in cancer-inducing quantities.
"Got a lot to do today?"
"I did, but I just shotgunned four business cokes. This shit is pringles."
"I'm sorry, you're going to have to quit your job in investment banking. You have business coke-induced cancer. Business cancer."