A complete control of the coupling between the modes of two photonic crystal microcavities is obtained by using a combination of several local tuning techniques. By a local and controlled modification of one cavity we are able to bring into resonance modes with a different polarization and spatial distribution, producing heteroatomic photonic molecules. Clear anticrossing is observed, denoting the mode hybridization which is in a very good agreement with finite difference time domain calculations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3475490]