No organization shall be exempt from taxation under section 501(a) by reason of being described in section 501(c)(3) whenever such organization is not treated as described in section 501(c)(3) by reason of section 508(a) and this paragraph. See section 508(d)(2)(B) and § 1.508-2(b) regarding the deductibility of charitable contributions to an organization during the period such organization is not exempt under section 501(a) as an organization described in section 501(c)(3) by reason of failing to file a notice under section 508(a) and this subparagraph. See also § 1.508-2(b)(1) (viii) regarding the deductibility of charitable contributions to trusts described in section 4947(a)(1).
If an organization fails to meet the requirements of (a), (b), or (c) of this subdivision, then with respect to the organization, such organization shall be required to file the notices described in section 508 (a) and (b) within 90 days after the end of the period described in (a), (b), or (c) of this subdivision or before March 22, 1973, whichever is later, in lieu of the period prescribed in subparagraph (2)(i) of this paragraph. Thus, for example, if an organization meets the $7,500 requirement of (a) of this subdivision for its first taxable year, but fails to meet the $12,000 requirement of (b) of this subdivision for the period ending with its second taxable year, then such organization shall meet the notification requirements of section 508(a)(1) and 508(b) and subparagraph (2)(i) of this paragraph if it files such notification within 90 days after the close of its second taxable year. If an organization which has been in existence at least 3 taxable years meets the requirements of (a), (b), and (c) with respect to all prior taxable years, but fails to meet the requirements of (c) of this subdivision with respect to the current taxable year, then even if the organization fails to make such notification within 90 days after the close of the current taxable year, section 508(a)(1) and 508(b) shall not apply with respect to its prior years. In such a case, the organization shall not be treated as described in section 501(c)(3) for a period beginning with such current taxable year and ending when such notice is given under section 508(a)(2).
26 C.F.R. §1.508-1
Secs. 508 and 7805 of the Internal Revenue Code of 1954 (68A Stat. 917; 26 U.S.C. 7805 )