Despite the importance of promoting online (offline) customers to buy offline (online), little is known about how such targeted promotions actually influence the web, in-store, and total sales. We exploit two randomized field experiment datasets from a large department store with mobile promotions sent to its loyalty members. Experiment 1 finds that the treatment of targeting online customers with offline shopping promotions (online-to-offline) is effective in lifting in-store sales and total sales. Experiment 2, however, finds that targeting offline customers with online shopping promotions (offline-to-online) increases web sales but fails to boost total sales. This targeting can be even harmful and reduce consumer total spending. Our findings do not support the channel-shift mechanism, because the targeted promotions may not always lead to sales that is substituted between the online and offline purchasing channels. Rather, they support the product category-shift mechanism, where offline (but not online) channel facilitates the purchases of touch and feel tactile products and new category sales with more unplanned purchases and cross-buying. The results demonstrate the value of omnichannel promotions and highlight the conditions under which online and offline targeting is most valuable for firms to promote the other channel.