Crito
The dialogue takes place in Socrates' prison cell, where he awaits execution. He is visited before dawn by his old friend Crito, who has made arrangements to smuggle Socrates out of prison to the safety of exile. Socrates seems quite willing to await his imminent execution, and so Crito presents as many arguments as he can in order to persuade Socrates to escape. On a practical level, Socrates' death will reflect badly on his friends--people will think they did nothing to try to save him. Also, Socrates should not worry about the risk or the financial cost to his friends; these they are willing to pay, and they have also arranged to find Socrates a pleasant life in exile. On a more ethical level, Crito presents two more pressing arguments: first, if he stayed, he would be aiding his enemies in wronging him unjustly, and would thus be acting unjustly himself; and second, that he would be abandoning his sons and leaving them without a father.
Chaerephon
In Plato's "Apology", an account of the Trial of Socrates in 399 BCE, Socrates calls Chaerephon his longtime friend and the friend of many present. Socrates says that Chaerephon is now deceased but indicates that his brother is in attendance at the trial. Socrates suggests that Chaerephon had a reputation for being impetuous and we learn that it was Chaerephon who journeyed to Delphi to ask the Delphic oracle who was the wisest of men. (The oracle replied that there was none wiser than Socrates.) Socrates also alludes to a period of exile which was endured by Chaerephon and some others present. This is sometimes taken as evidence that Chaerephon, unlike Socrates, was an active supporter of the Athenian Democracy and was persecuted on this account when the democracy was temporarily deposed after the defeat of Athens by Sparta.