A mechanistic mo del of the pyrolysis chemistry of 4-(1-naphthylmethyl)bibenzyl (NBBM) was developed. The elementary steps within NBBM hydropyrolysis reaction families were summarized in the form of reaction matrices, each with a set of associated rules. The pyrolysis model was constructed through the application of the matrices and rules to the components of the reacting system. The kinetics within each reaction family were constrained to follow Polanyi relationships. The Polanyi relation parameters were regressed to fit the model predictions with observed experimental yields for NBBM hydropyrolysis at 420 degrees C. The model was validated by the close agreement between experimental findings and model predictions and then used to probe the controlling mechanisms of NBBM pyrolysis.