The preparation of carboxylic acids from arylacetylenes has traditionally been carried out by ozonolysis or other harmful oxidants, alone or in presence of some metal catalysts. In spite of the safety, availability and environmental benignity of molecular oxygen, the selective cleavage of unsaturated hydrocarbons mediated by the latter oxidant has been rarely reported. Herein we wish to present the efficient preparation of carboxylic acid derivatives  from alkynes employing molecular oxygen as the only oxidant and in the presence of a Ni(II) salt and 1,2,4-triazole ligands