The supramolecular structures of the title compounds, 2-phenyl-5-p-tolyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(23)H(21)N(3), (I), 5-(4-bromophenyl)-2-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(18)BrN(3), (II), 2-(4-chlorophenyl)-5-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(18)ClN(3), (III), and 5-(4-bromophenyl)-2-(4-chlorophenyl)-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(17)BrClN(3), (IV), are of two general types. Compounds (I), (II) and (III) form base-paired dimers via N-H.N hydrogen bonds, where (I) and (II) are isomorphous, while in (IV), there are no conventional hydrogen bonds.