Known for
Nightlife around Nana and Asok, and the Japanese strip at Thong Lo.
Where people stay and go out
Asok to Ekkamai
Sukhumvit, Thong Lo, Ekkamai
The long road from Nana to Ekkamai: hotels, sois with food, Thong Lo, and nightlife closer to Asok. It is not one square. It is the line the city rides on the BTS.

Nightlife around Nana and Asok, and the Japanese strip at Thong Lo.
Come in the evening, when people go out to eat. By day there is the road and the shops by the stations, not a set of monuments.
The simplest base in Bangkok: plenty of rooms, food downstairs, the train overhead. Farther toward Ekkamai it gets quieter and more local.
Fedor Samorodov · guide
As far as soi 21 it is loud and touristic. Farther on, toward Thong Lo and Ekkamai, people eat more quietly: Japanese kitchens and local sois, not the bars at Nana.