First theoretical probe for alkynyl bridged thiophene modified coumarin nonlinear optical materials with D-π-A and A-π-D-π-A structures

First-principles exploration is very important to molecular design. In this study, geometric structure, intramolecular charge transfer (ICT), energy levels, polar moment, and ultraviolet–visible (UV–Vis) spectroscopy of eight novel and different alkynyl bridged thiophene modified coumarin nonlinear optical molecules with [Formula: see text]-[Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text]-[Formula: see text]-[Formula: see text]-[Formula: see text] structures had been studied by density-functional theory (DFT) calculations within B3LYP hybrid functional using 6-31 [Formula: see text], [Formula: see text] Gaussian type molecular-orbital basis set. This has guiding significance for the design of nonlinear optical molecules and the development of coumarin-based photoelectric molecules.