Various social factors attract Online buyers to a cutting-edge platform called social commerce. This study investigates the features of social commerce platforms, such as peer communication, that affect shoppers’ purchase intentions. It draws on insights from the stimulus-organism-response (S-O-R) and information processing theories. A survey of 387 consumers was conducted online on the well-known social commerce platform (Weitao) in China. This mediation model is examined using PLS-SEM (partial least squares structural equation modeling). The results show that (1) perceived diagnosticity, information quality, and buy intention, (2) peer communication and perceived diagnosticity, information quality, and (3) the mediating role of perceived diagnosticity and perceived information quality all have favorable connections. Overall results suggest that tie strength could alter consumer purchasing intentions through diagnosticity and information quality. The study offers fresh perspectives on consumer behavior in social commerce and its theoretical and practical ramifications.