(2,4,6-Trinitrophenyl)guanidine (picrylguanidine), C7H6N6O6, from the reaction of picrylsulfonic acid with guanidine carbonate, forms a three-dimensional framework structure through extensive hydrogen-bonding interactions, extending the centrosymmetric cyclic R22(16) dimer association which includes duplex R22(8) guanidine N-H...Onitro interactions. The guanidine substituent chain has an endo [Ph-N=C(NH2)2] bond sequence rather than the less sterically encumbered exo [Ph-NH-C=NH(NH2)] sequence of the tautomeric form. As a result, there is significant bond-angle distortion about C(-N=) of the aromatic ring.