The effects of propargyl alcohol (PA), propynol ethoxylate (PME), propargyl sulfonate (PS), and diethylaminopropyne (DEP) compounds as additives in a Watts bath on coating brightness, thickness, and efficiency were investigated and compared using electrochemical methods such as linear and square wave voltammetry (SWV), chronoamperometry, chronopotentiometry, electrochemical impedance (EIS), and X-ray fluorescence (XRF) spectroscopy. The charge transfer resistance values obtained in the presence of PA and PME were similar and higher than the other values obtained; this result suggests that PA and PME have better adsorption. The optic and XRF measurements revealed that for the PS molecule the plating is the brightest, and its leveling effect is the highest at the high current density, while the PA molecule has the same effect at low current density. The surface coverage (theta) values of the PS and PA molecules were determined from adsorption isotherms and the results show that PA has higher % theta. In addition, the optimization of PA, PME, PS, and DEP molecules was performed using a RHF basis set, and the results agreed with the experimental results. The SEM results obtained in the presence of additives revealed that brighter and smoother surfaces were obtained at low concentrations.