Nitrogen-doped graphene nanoplatelets (N-GNP) with 1.6-3.3 at.% nitrogen content were synthesized by thermal annealing of GNP functionalized with a series of imidazole-based nitrogen-containing precursors of different nature, charge and nitrogen content. The imidazole derivatives included one ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) and two polymers, a neutral one, poly(vinylimidazole) (PVI) and a poly(ionic liquid), poly(3-butyl-1-vinylimidazolium bromide) (PBVIBr). N-GNP showed enhanced electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline media compared to pristine GNP, with the number of electrons transferred in oxygen-saturated KOH at low overpotentials following the trend: 2.5 (pristine GNP) < 2.9 (N-GNP from PVI-GNP) < 3.3 (N-GNP from BMIBF4-GNP) < 3.5 (N-GNP from PBVIBr-GNP). Interestingly, ORR catalytic activity did not correlate with total nitrogen content but was more affected by Brunauer-Emmett-Teller (BET) surface area. The most active materials were N-GNP with lowest doping levels and highest surface area resulting from the ionic (imidazolium-based) nitrogen precursors. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.