Seven of the eight titles here (the absentee is the Semele) are also listed by Diogenes Laertius 6.80, amongst the works attributed to Diogenes of Sinope the well-known Cynic philosopher (delta 1141, delta 1143, delta 1144); however, D.L. himself notes that the attribution is questionable. So the present entry exhibits only one definite level of confusion: between this Diogenes and Oinomaos [Author, Myth] of Gadara, a quite different (and much later: C2 CE) Cynic philosopher (omicroniota 123). It remains unclear how many men called Diogenes were writing tragedies in classical Athens, but 'Athenian' here, if interpreted strictly, must rule out the Cynic, and two individuals are distinguished in (e.g.) Snell, TGrF pp.185 and 254-8.
[1] Or: was born.
[2] i.e. the suppression of Athenian democracy by the Thirty, a.k.a Thirty Tyrants: 404/3 BCE.