Social entrepreneurs who use market mechanisms to solve wicked problems (Rittel & Webber, 1973) may benefit from practices based on design thinking. Design thinking offers approaches to work iteratively on both problem and solution spaces collaboratively with multiple diverse stakeholders, which is characteristic of innovating for social change. This research conceptualizes designing as a construct formed by three practices: making improvements, generating creative leaps, and problemsolving. Using Boland and Collopy's (2004) conception of a sensemaking manager, it proposes "how" nascent social entrepreneurs take actions and also proposes "what" specific activities they undertake for the development of the venture. A conceptual model proposing "what" it is that social entrepreneurs do and "how" they go about their activities affecting new venture development is tested using structural equation modeling. Preliminary support for the predictive capability of the model is encouraging, suggesting that practices based on design thinking may be further developed in order to advance theoretical understanding of the application of design thinking for social entrepreneurship.