This paper explores the relationship between corporate social responsibility (CSR) and timeliness of goodwill impairment. Goodwill is the premium that is paid when a business is acquired. If the value of the business declines, goodwill impairment occurs. Deliberately delaying goodwill impairment (timeliness) is a widespread ethical issue. Based on all the mergers of Chinese listed companies during 2010–2019, we study the motivation of corporate charitable donations when facing the risk of goodwill impairment. Our results suggest that long-term (consistent) charitable donations reflect more altruist social responsibility than short-term (suddenly increased) donations. In particular, firms that make more long-term donations tend to report goodwill impairment timely, while firms making excessive short-term donations are more likely to delay goodwill impairment. Furthermore, we find that short-term donation is motivated not only to cover up the goodwill impairment delay, but also to provide insurance-like protection when delayed impairment is announced. Our results also suggest that moral licensing plays a role in inducing such opportunistic behaviors. To address the endogeneity problem, we use the number of provincial charitable funds and the number of provincial deaths due to natural disasters as instrumental variables for short-term excessive donations.