H1B to F1 after applying for Green Card

Consult an attorney before you apply for both the EB-1 (difficult to obtain and you may have other options) and the F-1. To obtain an F-1 you must have no intention of abandoning your foreign residence. In other words, when you apply for your F-1 the consular officer must be satisfied that you intend to depart the U.S. upon termination of your student status. If you have a pending immigrant petition at the time, this will be impossible to show. You have several options. Thus, consult with an immigration attorney to review them.

Ms. Delacruz is correct that once you have filed an EB1 case (particularly a self-petition), you will not be eligible for an F-1 visa, having expressed immigrant intent. However, you should meet with an attorney who handles EB1 cases, and bring as much documentation of your academic achievements and renown as you can provide, to get a realistic assessment of the strength of your case, because if you have a strong EB1 case, you could obtain residence within the coming 2 years, and wouldn't need an F-1 to attend business school.