Four men used aid convoys bound for Syria to transport items that would be used to commit terrorism offences, a court heard.
Syed Hoque, 37, of Stoke-on-Trent, allegedly handed over £3,000 and a further sum of £1,500 on December 21 2013, to help his nephew who was fighting against the regime in the war-torn country.
He is also accused with three other men of making "other property" available between December 1 2012 and May 31 2014.
Mashoud Miah, 27, of east London, Mohammed Hussain, 30, of east London, Pervez Rafiq, 46, of Birkby, Huddersfield, and Hoque all deny the charge.
Hoque denies a further two counts of funding terrorism.
Prosecutor Annabel Darlow QC, said: "The defendants made use, or so it would appear, of aid convoys as a means of moving money and other property out of the UK to Syria."
Adding that it was not the suggestion the convoys did not have a legitimate charitable purpose, she continued: "Normal routes are not much use when you look at Syria.
"So if you do want to get property or money out to Syria, the convoys would have provided a useful conduit. And you may think that an abuse of the spirit of the convoys to convey the money and property to terrorists."
Jurors at the Old Bailey were told that on August 5 2014, Hoque and his wife were stopped at Heathrow airport after returning from Bangladesh.
Their phones were taken from them and the data downloaded. As initial examinations did not reveal any extremist material, the phones were returned.
However, subsequent analysis showed Hoque had been communicating via WhatsApp with a person known as Sayyaf who was using a Turkish number.
This man was later found to be Hoque's nephew Mohammed Choudhury, who was in Syria and was fighting on behalf of Jabhat al-Nusra, a terrorist organisation representing the wing of al Qaida in Syria, the court heard.
Jurors heard the messages revealed Hoque had been supplying Choudhury with money and that the two men had discussed the possibility of buying a Dragunov sniper rifle, an AK assault rifle and a nightscope.
Ms Darlow said the correspondence showed Hoque was aware his nephew was "engaged in military conflict and that he sought, by violent means, the death and destruction of the Syrian president and that part of the population that supported the Syrian president".
"Mr Hoque actively encouraged Choudhury in these goals and repeatedly both provided and offered to provide financial and other support to Choudhury."
She added that Hoque knew Choudhury was on training missions in relation to improvised explosive devices and the firing of arms, and that he handled military grade weaponry.
"On occasions Mr Hoque even had to rein in some of Choudhury's worst excesses. In the course of one particularly graphic exchange, advising him to behead his enemies in Syria, but suggesting he should draw the line at mutilating their bodies," the prosecutor told jurors.
Hoque is accused of sending a total of £4,500 to his nephew in Syria in 2013.
It is alleged that Miah's role was that of a facilitator who could be turned to when an address or contact was required, as he had spent a lot of time in Syria.
He was also known as Abu Esa, and with Hoque was in contact with Hussain.
Hussain knew Rafiq and it is alleged that on October 2 2013, passed some items - that had been on Miah's list - to Rafiq before he set out in a charity convoy to Syria.
The prosecution say there is no direct evidence as to what items were passed between the men.
Ms Darlow said: "It is the case for the prosecution that each of these four defendants involved themselves in an arrangement - and in Mr Hoque's case, more than one arrangement - by which property was to be made available to those fighting in Syria in the conflict against the existing regime.
"In the case of Syed Hoque, the property included money intended at least in part to be used to provide a firearm to his nephew, who was fighting out in Syria and fighting with the purpose of overthrowing the existing regime in Syria.
"Each of the defendants also became involved in an arrangement to obtain items which included a satellite phone, SatNavs and sophisticated ballistics software."