Things become simper if they follow a rule. The design of functional materials also like this whereas a good building unit may readily result in abundant materials with diversified properties. It was closely related to the features of the choosing building unit. In this summary, we bring an introduction of functional materials built by an aggregation-induced emission (AIE) unit of tetraphenylpyrazine (TPP). The characteristics of facile synthesis, good stability, strong electron affinity, rich nitrogen sites and suitable molecular symmetry, and conformation twist are attractive. From one core unit, the multiple applications in sensing, photosensitizer, waveguide, metal-organic framework, and organic solar cells can be realized pleasantly.