A new class of chromophores has been fabricated that features both electron-releasing and electron-withdrawing groups fused via an intervening ethynyl moiety to the carbon framework of a (porphinato)metal complex. These species possess large molecular first-order hyperpolarizabilities (β). We report herein the synthesis, optical spectroscopy, and the hyper-Rayleigh scattering data used to determine the β values of two archetypal members of this new class of exceptional nonlinear chromophores: [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]copper(II) and [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]zinc(II). One of these compounds, [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]zinc(II), possesses β values near 5000 × 10-30 esu at incident irradiation wavelengths of both 830 and 1064 nm. These studies suggest that this chromophoric structural motif may find utility...