EXHIBIT 4.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the reference to our firm under the caption "Experts-Independent Registered Public Accounting Firm" and to the use of our report dated March 9, 2020 in the Amendment No. 1 to the Registration Statement (File No. 333-236134) and related Prospectus of Guggenheim Defined Portfolios, Series 1994. /s/ Grant Thornton LLP ---------------------- GRANT THORNTON LLP Chicago, Illinois March 9, 2020