Grounded theory is a general research methodology, a way of thinking about and conceptualizing data. It is used by nonprofit maintaing sustainability in studies of diverse populations from rural areas as well as urban areas for getting the status of inclusive education in society. People can explain what they feel is lacking in inclusive education. Researchers from Nonprofit maintaing sustainability then may gather this data, examines the results to discover the root cause of their problems and presents solutions.
I would think stakeholder theory could be relevant to nonprofits. It is also possible to look at concepts related to corporate social responsibilty (CSR).
The guidance and views as per the following papers may further help:
Dart, R. (2004) Being “business-like” in a nonprofit organization: A grounded and inductive typology, Nonprofit and voluntary sector quarterly, 33, 2, pp. 290-310.
Kandaiya, T. and Chavan, M. (2013) Social enterprise and sustainability: A theoretically grounded approach to strategy development, International Journal of Interdisciplinary Environmental Studies, 7, 1, pp. 55-70.
Weerawardena, J., McDonald, R. E. and Mort, G. S. (2010) Sustainability of nonprofit organizations: An empirical investigation, Journal of World Business, 45, 4, pp. 346-356.
Weerawardena, J. and Mort, G. S. (2006) Investigating social entrepreneurship: A multidimensional model, Journal of World Business, 41, 1, pp. 21-35.