Metal‐free synthesis of [Hg‐{1‐C6H4‐2‐(imidazolidine)}{1′‐C6H4‐2′(‐CHN‐CH2)}]2 (8a) was achieved by (2+2) cyclocondensation of bis(2‐formylphenyl)mercury(II) (6) with diethylenetriamine. The macrocycle exists as a mixture of tautomers 8a and [Hg‐{1,1′‐(C6H4)2‐2,2′‐(CHN)}2‐C2H4NHC2H4]2 (8b). The cyclization was facilitated by Hg···N intermolecular interaction. DFT calculations of tautomers favor the formation of the ring tautomer 8a over the chain tautomer 8b by 18 kcal mol–1. The reduction of a mixture 8a and 8b with sodium borohydride gave a mixture of 28‐membered reduced mercuraazamacrocycle [Hg‐{1,1′‐(C6H4)2‐2,2′‐(CH2NH)}2‐C2H4NHC2H4]2 (12) and 8a. Macrocycle [Hg‐{1,1′‐C6H‐2,3,4‐(OCH3)3‐6,6′‐(CHN)}2‐C2H4NHC2H4]2 (9) was synthesized by (2+2) dipodal condensation of bis(6‐formyl‐{2,3,4‐trimethoxy}phenyl)mercury(II) (7) with diethylenetriamine to obtain the 28‐membered chain tautomer of macrocycle 9. Reaction of 7 with diethylenetriamine did not give the ring tautomer. 32‐Membered selenium‐ and tellurium‐containing Schiff base macrocycles [Hg‐{1,1′‐C6H‐2,3,4‐(OCH3)3‐6,6′‐(CHN)}2‐ C3H6SeC3H6]2 (10), [Hg‐{1,1′‐C6H‐2,3,4‐(OCH3)3‐6,6′‐(CHN)}2‐C3H6TeC3H6]2 (11), and mercuraazametallocryptand [Hg‐{1,1′‐C6H‐2,3,4‐(OCH3)3‐6,6′‐(CHN)}2‐{N(C2H4)3}]2 (12) were obtained by (2+2) condensation of bis(6‐formyl‐{2,3,4‐trimethoxy}phenyl)mercury(II) (7) with 3,3′‐selenobis/telluorobis‐1‐propanamine and tris(2‐aminoethyl)amine respectively.