This invention relates to an accelerator composition particularly adapted for providing extended shelf life to sheet and bulk molding compound while providing for accelerated cure rates at molding temperatures. The accelerator composition comprises in combination:A cobaltic promotor selected from the group consisting of cobaltic halides, cobaltic salts of monocarboxylic acids having from 2 to 20 carbon atoms, cobaltic sulfate, and cobaltic beta-diketones; andFrom about 1 to 4,500 parts, per part of cobaltic metal in said cobaltic promoter, of a coupler selected from the group consisting of oxides and hydroxides of calcium and magnesium.