Low thermal expansion block polyimide and its precursor and its use

An object of the present invention is to obtain a polyimide having cyclohexanediamine as a diamine unit and having a low thermal expansion coefficient at a low cost. The present invention provides a block polyimide comprising a block composed of a repeating structural unit represented by the following formula (1A) and a block composed of a repeating structural unit represented by the following formula (1B). The block polyimide is a block polyamic acid imide containing a block composed of a repeating structural unit represented by the following formula (2A) and a block composed of a repeating structural unit represented by the following formula (2B). It is preferable to obtain by imidization. [Chemical 1]