Abstract <p>Nonlinear optical materials have potential applications in optical signal processing, photovoltaic conversion, and optical information storage. As organic conjugated material, its high second-order nonlinear optical (NLO) properties can be produced due to the introduction of alkali metal species on porphyrin surface. In order to investigate the effects of alkali metal atoms on the second-order NLO properties of porphyrin derivative (PYD) complexes, a series of novel alkali metal porphyrin derivatives (M@PYD and M₂F@PYD, M&#xa0;=&#xa0;Li, Na, K) are systematically studied using the density-functional theory calculations. Firstly, the stable structures of all the complexes are confirmed, and the high chemical stability of alkali metal porphyrin complexes is explored by the analysis of binding energy. The nonlinear optical properties of stable structures are analyzed to obtain the dipole moments, polarizabilities and the static first hyperpolarizabilities of the functionalized complexes. The calculated results show that the system has the maximum static first hyperpolarizability (β₀&#xa0;=&#xa0;2457.573&#xa0;a.u.) when the Na₂F molecule is introduced onto the PYD surface, whereas M@PYD has relatively small static first hyperpolarizability. The present findings will provide the important reference for designing the high-performance porphyrin-based NLO materials.</p>