Crystal structure of a second polymorph of tetra­kis­(pyridin-2-yl)methane

A second polymorph of the title compound, C21H16N4, is reported. The original polymorph was solved by our group [Matsumoto et al. (2003). Tetra­hedron Lett. 44, 2861–2864] in the monoclinic space group C2/c and refined to R = 0.050. Now the crystal structure of a tetra­gonal polymorph (space group P-421c) has been solved and refined to R = 0.036. In the crystal, there are no strong inter­molecular inter­actions. Reflecting the high symmetry of the mol­ecular structure, the asymmetric unit is a quarter of the mol­ecule, and the mol­ecule exhibits S4 symmetry along the c axis in the crystal.