3-tert-Butyl-7,7-dimethyl-1-phenyl-5,6,7,8-tetrahydroimidazo[3,4-b]quinolin-5-one and 2,8,8-trimethyl-5-phenyl-6,7,8,9-tetrahydroimidazo[2,3-a]quinolin-6-one: chains generated by C-H...N hydrogen bonds.

In both 3-tert-butyl-7,7-dimethyl-1-phenyl-5,6,7,8-tetrahydroimidazo[3,4-b]quinolin-5-one, C22H25N3O, (I), and 2,8,8-trimethyl-5-phenyl-6,7,8,9-tetrahydroimidazo[2,3-a]quinolin-6-one, C19H19N3O, (II), the heterobicyclic portions of the molecules are planar, with naphthalene-type delocalization in (II), while the carbocyclic ring in each compound adopts an envelope conformation. In both (I) and (II), the molecules are linked weakly into chains by a single C-H...N hydrogen bond.