This article offers the research of ways of complication of a subordinate-coordinate polynome, an art of complex clauses, which is made of at least three constituents. Each constituent – a clause is a participant of subordinate relations. There are additionally coordinative relations between a pair of subordinate clauses in the sentence. The study is undertaken on the material of the scientific discourse. The analyzed 500 subordinate-coordinate polynomes were chosen from scientific journals of the period from 2015 to 2017. It was discovered, that for two thirds of polynomes it is typical to broaden its basic triangle form and to add new predicative or half-predicative constructions. Among all existing ways of complication (widening, extension, including), only two (widening and including) are used to streamline the syntactical structure of subordinate-coordinate polynomes. If a polynom is extended, so one or more main clauses are added, it stops to be a subordinate-coordinate polynome and becomes a coordinate-subordinate one. Such sentences were not analyzed in this research, because such sentences are not subordinate-coordinate polynomes anymore. The typical way of complication is widening of a polynome, that occurs when a) one or more subordinate clauses are added to the pair of coordinate clauses in the sentence or b) when a word in a clause or the whole main or subordinate clause is specified. Almost half of studied examples were complicated several times. That means that even such a close and balanced construction as a subordinate-coordinate polynome can be changed according to the needs of the author. More than a half of subordinate clauses are directly connected with the main one. From possible 6 levels of setting a hierarchical connection between clauses like a connection between a subordinate clause and a main one only five are evidential. When the structure of a polynome is getting more complicated, some processes of simplification are used parallel: ellipsis, reduction of a subordinate clause etc. The second way of complication of a polynome is including half-predicative constructions. In the analyzed polynomes only 2 from 3 half-predicative constructions were found: infinitive and adverbial participial phrases. There were no polynomes with absolute constructions, which also belong to half-predicative ones. The quantity of infinitive phrases is more than ten times higher than the quantity of adverbial participial ones. It is typical for polynomes to add infinitive phrases with Infinitive Simple Active. In a such way these phrases show an activity which happens parallel to the predicate in the clause. By contrast to this, adverbial participial phrases include Participle 2 Active, that shows a finished action, which has happened before the action in the clause with what it’s connected. Anyway, including a half-predicative construction is much less typical for polynomes in the scientific discourse than adding a clause, so a full predicative construction. The perspective of this research can be an investigation of subordinate-coordinate polynomes in other discourses (mass media, literature etc.) and the comparison of their features with the features of the polynomes in the scientific discourse. Another sphere of a further research is a study of the communicative organization of subordinate-coordinate polynomes in different discourses and an investigating of the differences between subordinate-coordinate and coordinate-subordinate polynomes.