Is it permissible to intentionally perform ablution and pray two rak'ahs with the intention of the Sunnah of ablution an hour before Maghrib on Friday, with the aim of catching the hour of acceptance (istijabah) and praying during it, and what should one do to catch this hour and supplicate during it?

Praying two rak'ahs after ablution is a Sunnah of those prayers with a specific reason, and it is permissible to perform them during the times when prayer is ordinarily prohibited, such as from after the 'Asr prayer until sunset. This is the view held by the Shafi'is and chosen by a group of scholars, including Ibn Taymiyyah.

However, it is disliked for a person to intentionally perform voluntary prayers during the times when prayer is ordinarily prohibited. The disliking here is specific to someone who intends to pray at that time, not to someone who happens to pray then by chance.

As for determining the time of the hour of acceptance (of supplications) on Friday, scholars have differed on this. Some preferred the view that it is the last hour of Friday, while others preferred that it is between the Imam's sitting on the minbar and the end of the prayer.