Complex sentence: He exhibited in the 1980s his Neo-expressionist and Primitivist paintings in galleries and museums internationally, but he died of a heroin overdose at the age of 27 in 1988.
Split into simpler sentences: He exhibited in the 1980s his Neo-expressionist and Primitivist paintings in galleries and museums internationally. Basquiat died of a heroin overdose at the age of 27 in 1988.