N.Y. Estates, Powers & Trusts Law § 3-1.3
testamentary dispositions to unincorporated associations
(b) When a will disposes of property to an association which lacks capacity to receive such property by will because it is unincorporated and the association may become incorporated under the law of this state or of the jurisdiction in which it has its principal office, such disposition is valid despite the lack of capacity of the beneficiary if within three years after probate of the will such beneficiary becomes incorporated with capacity to take such disposition, subject to the following: