The syntheses of 1-methyl-, 1,1-dimethyl-, cis(?)-1,2-dimethyl-, 1,1,2-trimethyl-, and 1,1,2,2-tetramethylacenaphthene have been accomplished by standard reactions from the two compounds 1-acenaphthenone and 2-methyl-1-acenaphthenone. These two ketones were in turn obtained from 1-naphthaleneacetic acid.