| 1 | 250-00-0 | Naphth[2,1-c]-1,2-oxathiete (8CI,9CI) | C10H6OS | 174.22 | | |
| 2 | 250-19-1 | 4-Oxatricyclo[4.3.0.02,8]nonane (8CI,9CI) | C8H12O | 124.18 | | |
| 3 | 250-20-4 | 3-Oxatricyclo[4.3.0.02,8]nonane (8CI,9CI) | C8H12O | 124.18 | | |
| 4 | 250-21-5 | Tricyclo[3.3.0.02,6]octane | C8H12 | 108.18088 | | |
| 5 | 250-22-6 | Tricyclo[3.2.1.03,6]octane (7CI,8CI,9CI) | C8H12 | 108.18 | | |
| 6 | 250-25-9 | Pentalene | C8H6 | 102.13 | | |
| 7 | 250-26-0 | Cyclopenta[c]pyrrole (8CI,9CI) | C7H5N | 103.12 | | |
| 8 | 250-35-1 | 1H,3H-Thieno[3,4-c]thiophene | C6H6S2 | 142.24 | 59-60 °C | |
| 9 | 250-36-2 | Cyclopenta[b]pyrrole | C7H5N | 103.12 | | |
| 10 | 250-59-9 | Furo[3,4-d]isoxazole (8CI,9CI) | C5H3NO2 | 109.08 | | |
| 11 | 250-63-5 | 5H-Thieno[2,3-c]pyrrole | C6H5NS | 123.18 | 68.5-69.5 °C | |
| 12 | 250-65-7 | Thieno[3,4-b]thiophene | C6H4S2 | 140.226 | | |
| 13 | 250-71-5 | Selenolo[3,4-b]selenophene | C6H4Se2 | 234.02 | | |
| 14 | 250-72-6 | Pyrrolo[2,3-b]pyrrole | C6H4N2 | 104.11 | | |
| 15 | 250-73-7 | Pyrazolo[3,4-c]pyrazole(8CI,9CI) | C4H2N4 | 106.08548 | | |
| 16 | 250-79-3 | 6H-Thieno[2,3-b]pyrrole | C6H5NS | 123.18 | | |
| 17 | 250-81-7 | Furo[2,3-b]furan | C6H4O2 | 108.09 | | |
| 18 | 250-84-0 | THIENO[2,3-B]THIOPHENE | C6H4S2 | 140.226 | 7°C(lit.) | |
| 19 | 250-87-3 | Pyrrolo[3,2-b]pyrrole | C6H4N2 | 104.11 | | |
| 20 | 250-91-9 | 4H-furo[3,2-b]pyrrole | C6H5NO | 107.11 | | |
| 21 | 250-94-2 | 4H-THIENO[3,2-B]PYRROLE | C6H5NS | 123.18 | 30-35 °C | |
| 22 | 250-971-1 | 35-Bis(trifluoromethyl)benzyl bromide | | | | |