Abstract: Disclosed herein are base-modified nucleoside-5?-oligophosphates (bm-N5OP) that include a positively charged moiety at least at one position of the base, compositions comprising the same, compositions made from the same, methods of making the same, and methods of using the same. The bm-N5OP disclosed herein are useful, for example, as tagged nucleotides for use in nanoSBS methods and for generating primers and/or templates for use in nanoSBS methods. When incorporated into a polynucleotide, the disclosed bm-N5OPs can neutralize at least a portion of the negative charge of the overall polynucleotide molecule.