The project aims to investigate the photophysical, spectroscopic, and supramolecular assembly properties of d8 square-planar metal complexes, as well as their applications in optoelectronics. This dataset includes characterization data of the complexes, featuring 1H NMR and high-resolution mass spectra, cyclic voltammograms, and XRD data. Additionally, UV-vis absorption and emission spectra, along with computational data, are provided for studying the photophysical and spectroscopic properties of the complexes. The dataset also contains dynamic light scattering data, electron micrographs, AFM images, and device performance data to support the studies of the supramolecular properties and optoelectronic applications of the complexes.