The reported synthesis of 1,2,3,4-tetraphenyldiazetidine by treating the sodium adduct of N-benzylidene aniline with benzaldehyde or benzoate ester is reexamined. It is shown that the original report is in error. The products from the reaction are the two diastereomeric N-benzoyl-N,N′,1,2-tetraphenylethylenediamines anddd,ll-N,N′, 1,2-tetraphenylethylenediamine. When diethyl ether was used as a reaction medium, another product, N-benzoyl-N,N′-diphenylstilbene-α,α′-diamine, was formed. An explanation is offered for the formation of these compounds and for the differences in reaction products caused by the two reaction media employed, diethyl ether and te trahydrofuran.