There are at least two artists with this name:
1) Ian Thomas (Canadian, active 1970's-Present)
2) Ian Thomas (American, active 2000's-Present)
3) Ian Thomas (Belgian, active 2011's-Present)
1) Canadian Ian Thomas:
Ian Thomas (born 23 July 1950, Hamilton, Ontario, Canada) is a Canadian singer, songwriter, actor and author. He is younger brother to famed Canadian comedian and actor Dave Thomas.
Thomas was a successful rock and roll musician in Canada during the 1970s, with his most memorable hit being 1973's "Painted Ladies". Read more on Last.fm