Start with a benzene ring bearing two para (opposite) substituents: one is a nitrile group (-C#N, a carbon triple-bonded to a nitrogen), the other is an -NH- that begins the side chain.

The side chain detains (from the ring outward):

1. The ring connected -NH- is acylated to give -NH-C(=O)-.
2. The carbonyl carbon is bonded to a methylene (-CH2-).
3. That methylene is attached to a secondary nitrogen (-NH-).
4. This nitrogen is bound to a sulfonyl group, i.e., -NH-SO2- (sulfur doubly bonded to two oxygens).
5. The sulfonyl sulfur is bonded to a thiophene ring (a five-membered aromatic ring with one sulfur atom) at the carbon adjacent to the ring sulfur. On the other adjacent carbon of that thiophene, there is a single chlorine substituent.