The paths connecting the stationary points of tesseract (four-dimensional hypercube) have beenexplored. The minimum energy conformations and the different transition states of N,N0-dinaphthyl imidazol-2- ylidenes and imidazolin-2-ylidenes have been calculated. The available experimental results were conveniently reproduced. The dimerization of carbenes to enetetramines has also been calculated. ©Springer Science+Business Media, LLC 2011.Peer Reviewe