Zajączek was formerly part of the German Empire. In the German Empire, the place was called Haasel.
The place is now called Zajączek and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Haasel | German Empire | Sorau (Lausitz) | 1939 |
| Zajączek | Under Polish administration | Żary | 1945 |
| Zajączek | Poland | Zielona Góra | 1992 |