The title compound, C(17)H(14)N(2)O, crystallizes as a cis formamide isomer. The isoquinoline and benzene fragments are nearly perpendicular [dihedral angle = 81.79 (18)°], whereas the formamide group is virtually coplanar with the isoquinoline unit [dihedral angle = 1.66 (15)°]. Inter-molecular N-H⋯O hydrogen bonds link mol-ecules into a centrosymmetric dimer.