2,5-Dimethyl-6,7-dihydrobenzo[h]pyrazolo[1,5-a]quinazoline and 2-tert-butyl-5-methyl-6,7-dihydrobenzo[h]pyrazolo[1,5-a]quinazoline.

In both 2,5-dimethyl-6,7-dihydrobenzo[h]pyrazolo[1,5-a]quinazoline, C(16)H(15)N(3), (I), and 2-tert-butyl-5-methyl-6,7-dihydrobenzo[h]pyrazolo[1,5-a]quinazoline, C(19)H(21)N(3), (II), which crystallizes with Z' = 2 in the space group P\overline{1}, the non-aromatic carbocyclic rings adopt screw-boat conformations. The molecules of (I) are linked into chains of rings by a combination of C-H...N and C-H...pi(arene) hydrogen bonds, while in (II) there are no hydrogen bonds of any kind.