Demosthenes was a Greek, and Skull and Bones is a secret society and fraternity (part of the Greek system). In addition, he was of great influence to his society, just as Skull and Bones is to ours. Also consider that Skull and Bones of Yale is located in ‘Connecticut’, connecting nicely with ‘Demosthenes’.
Furthermore, notice that he lived from 384 BC to 322 BC, 62 years later, connecting with the state.
And of course he died in 322 BC, and Skull and Bones is at building 322.