A method of fabricating polynucleotide arrays includes dissolving a nucleotide monomer, oligonucleotide, or polynucleotide in a solvent containing ionic liquid and depositing the resulting solution on an array substrate. The method has particular application to fabrication of an addressable array of polynucleotides on a substrate that carries substrate bound moieties each with a hydroxyl group. The process may be repeated at specific locations on the array to elongate the polynucleotide deposited on the array.