In the following years Demetrius did not abandon his desire to unify the Hellenistic world, which had been smashed to pieces at Ipsus. The second battle of Seleucus I for which we have a relatively detailed record, the battle of Cyrrhestica in 285 B.C., brought this hope and Demetrius' career to an end.

After losing Macedon, which had been his base of power, to Lysimachus and Pyrrhus in 287 B.C. (Plut. Demetr. 44), Demetrius escaped to Asia Minor with a small army of mercenaries, determined to recover his father's Asian Empire. At first he tried to stir the Ionian cities to rebellion, but the appearance of Agathocles, son of Lysimachus, compelled him to turn eastwards. His plan was now to reach Media, then under Seleucus' control, and with the help of the soldiers settled there by his father reconquer the east. But the troubles and hardship he met on his flight from Agathocles and the soldiers' refusal to set off on the long expedition to Media forced him to try to come to terms with Seleucus and ask him for a small territory on the northern slopes of the Taurus. After being turned back, and after some preliminary skirmishes in Cilicia, Demetrius played his last card. He invaded Syria and arrived at Cyrrhestica with his small mercenary force (ibid. 46–8; Polyaenus 4.7.12).