Examples of Singing: "Memories (Part II)," "24K of Gold," "Don't Tell Me You Love Me," "I'm Gonna Be"
Big Sean's never sang on his singles, but as soon as you delve a bit into his catalog, there are plenty of examples. He's only one album into his career, so there's the possibility that his singing will become more prevalent as he grinds on.

Conclusion: Sure, Big Sean likes to hold a tune when he can, but he's more focused one earning respect as a rapper first.