The present invention provides plating solutions, particularly copper plating solutions, designed to provide uniform coatings on substrates and to provide substantially defect free filling of small features formed on substrates with none or low supporting electrolyte, i.e., which include no acid, low acid, no base, or no conducting salts, and/or high metal ion, e.g., copper, concentration. Defect free filling of features is enhanced by a plating solution containing blends of polyethers (“carrier”) and organic divalent sulfur compounds (“accelerator”), wherein the concentration of the carrier ranges from about 0.1 ppm to about 2500 ppm of the plating solution, and the concentration of the accelerator ranges from about 0.05 ppm to about 1000 ppm of the plating solution. The plating solution is further improved by adding an organic nitrogen compound at a concentration from about 0.01 ppm to about 1000 ppm to improve the filling of vias on a resistive substrate. The organic nitrogen is preferably a substituted thiadiazole, which is used at concentrations from 0.1 ppm to about 50 ppm of the plating solution, or a quartenary nitrogen compound, which is used at concentrations from about 0.01 ppm to about 500 ppm.