A search for decays of B c + mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0fb −1 , collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are B c + →D (s) (⁎)+ D‾ (⁎)0 and B c + →D (s) (⁎)+ D (⁎)0 , which are normalised to high-yield B + →D (s) + D‾ 0 decays. No evidence for a signal is found and limits are set on twelve B c + decay modes.