A complex business process demands adaptability as it has been highly influenced by the contextual information. The contextual information declares the underlying semantics on which the process logic depends. Thus one of the challenges of a business process modeling is to include the context sensitivity within the modeling itself. BPMN is the widely accepted tool in this field. All the process modeling languages like EPC, UML, BPMN are not able to express the context awareness as required. In this paper an attempt has been made to offer a means for modeling a complex business process with necessary contextual information. We have proposed a context model in terms of a graph, extended the existing BPMN by adding new construct and integrated the said components to achieve our goal. The methodology as stated certainly offers necessary understandability, maintainability and the adaptability as a whole. Moreover the model is validated using Colored Petri Net and is expected to behave properly in a real life environment.