Progress toward sustainability will require innovation and collaboration among business, government and civil society. But progress in recent years has been marked by trial and error, scepticism and confusion, and poor coordination across sectors. This paper proposes a framework for identifying and understanding opportunities for more effective collaboration. The framework distinguishes between four quadrants of opportunity for promoting corporate social responsibility. The structural foundation quadrant addresses behavior required by current law. The social foundation quadrant addresses behavior required by society's current norms and expectations. The structural frontier quadrant addresses practices that benefit society, but not necessarily the individual corporation. The strategic frontier quadrant addresses practices that may benefit society and the firm. Each quadrant can provide opportunities for collaboration. But the opportunities differ in each quadrant, requiring different tactics by each sector and raising different requirements for success.