Brazilian vacuum residue (VR) was separated into insoluble and soluble fractions using n-heptane-toluene mixtures (Heptol). Coking tests performed on the soluble fractions showed that asphaltenes vary in regard to the extent to which they form coke. VR asphaltenes were subfractioned into AS 0-10%, AS 10-20%, AS 20-30%, and AS 30-40% by stepwise extraction using Heptol. The AS 20-30% and AS 30-40% fractions had greater aromaticity and a higher proportion of quaternary aromatic carbons, as well as a larger unit size. These type II asphaltenes produced more coke than did type I asphaltenes, which consist of the AS 0-10% and AS 10-20% fractions.