When he was grown, Zeus forced his father to vomit up his siblings, who rebelled against the Titans. Zeus released the Cyclopes and Hecatoncheires, who became his allies. While the Hundred-Handed Giants fought alongside Zeus and his siblings, the Cyclopes gave Zeus his great weapon, the thunderbolt, with the aid of which he was eventually able to overthrow the Titans, establishing himself as the ruler of the cosmos. Homer
In Book 9 of the Odyssey, Odysseus describes to his hosts the Phaeacians his encounter with the Cyclops Polyphemus. Having just left the land of the Lotus-eaters, Odysseus says "Thence we sailed on, grieved at heart, and we came to the land of the Cyclopes". Homer had already (Book 6) described the Cyclopes as "men overweening in pride who plundered [their neighbors the Phaeacians] continually", driving the Phaeacians from their home. In Book 9, Homer gives a more detailed description of the Cyclopes as:

an overweening and lawless folk, who, trusting in the immortal gods, plant nothing with their hands nor plough; but all these things spring up for them without sowing or ploughing, wheat, and barley, and vines, which bear the rich clusters of wine, and the rain of Zeus gives them increase. Neither assemblies for council have they, nor appointed laws, but they dwell on the peaks of lofty mountains in hollow caves, and each one is lawgiver to his children and his wives, and they reck nothing one of another.
But Cronus once again bound the six brothers, and reimprisoned them in Tartarus.As in Hesiods account, Rhea saved Zeus from being swallowed by Cronus, and Zeus was eventually able to free his siblings, and together they waged war against the Titans. According to Apollodorus, in the tenth year of that war, Zeus learned from Gaia, that he would be victorious if he had the Hundred-Handers and the Cyclopes as allies. So Zeus slew their warder Campe (a detail not found in Hesiod) and released them, and in addition to giving Zeus his thunderbolt (as in Hesiod), the Cyclopes also gave Poseidon his trident, and Hades a helmet (presumably the same cap of invisibility which Athena borrowed in the Iliad), and "with these weapons the gods overcame the Titans".Apollodorus also mentions a tomb of Geraestus, "the Cyclops" at Athens upon which, in the time of king Aegeus, the Athenians sacrificed the daughters of Hyacinth. Nonnus
Dionysiaca, composed in the 4th or 5th century BC, is the longest surviving poem from antiquity – 20,426 lines. It is written by the poet Nonnus in the Homeric dialect, and its main subject is the life of Dionysus. It describes a war that occurred between Dionysus troops and those of the Indian king Deriades. In book 28 of the Dionysiaca the Cyclopes join with Dionysian troops, and they prove to be great warriors and crush most of the Indian kings troops.