![Molecular structure of Thieno[3,2-b]thiophene (CAS 251-41-2)](/images/chem_structures_svg/381/251-41-2.svg)
Thieno[3,2-b]thiophene
Also known as: 1,4-Dithiapentalene, 1,4-Thiophthene, Thieno[3,2-b]thiophen, thieno(3,2-b)thiophene, thienothiophene
Thieno[3,2-b]thiophene (CAS 251-41-2) is a compound in the Pharma Intermediates category listed in the Jingsj chemical database. It has the molecular formula C6H4S2 and a molecular weight of 140.23 g/mol. Key properties include a melting point of 56ºC, a boiling point of 223.4±13.0 °C at 760 mmHg, a density of 1.4±0.1 g/cm3 and a flash point of 63.1±6.0 °C. It is classified under GHS with signal word Warning and hazard statements H302 — Harmful if swallowed, H315 — Causes skin irritation and H319 — Causes serious eye irritation. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.
- CAS No.
- 251-41-2
- Jingsj CID
- J-40673-5
- Molecular Formula
- C6H4S2
- Molecular Weight
- 140.23 g/mol
- Category
- Pharma Intermediates
- Last updated
- 8/21/2026
No offers for this compound yet.
Request a quotePhysicochemical Properties
| Melting Point | 56ºC |
|---|---|
| Boiling Point | 223.4±13.0 °C at 760 mmHg |
| Density | 1.4±0.1 g/cm3 |
| Flash Point | 63.1±6.0 °C |
| Exact Mass | 139.975433 |
| PSA | 56.48000 |
| LogP | 5.31 |
| Vapor Pressure | 0.1±0.4 mmHg at 25°C |
| Refractive Index | 1.729 |
GHS Safety & Compliance
- H302 — Harmful if swallowed
- H315 — Causes skin irritation
- H319 — Causes serious eye irritation
- H335 — May cause respiratory irritation
Customs & Trade Information
| HS Code | 2934999090 |
|---|---|
| Summary | 2934999090. other heterocyclic compounds. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:20.0% |
Frequently Asked Questions
What is the CAS number of Thieno[3,2-b]thiophene?
The CAS number of Thieno[3,2-b]thiophene is 251-41-2.
What are the molecular formula and molecular weight of Thieno[3,2-b]thiophene?
Thieno[3,2-b]thiophene has molecular formula C6H4S2 and molecular weight 140.23 g/mol.
Is Thieno[3,2-b]thiophene hazardous?
Thieno[3,2-b]thiophene has GHS signal word Warning and hazard statements H302 — Harmful if swallowed; H315 — Causes skin irritation; H319 — Causes serious eye irritation.
What are the upstream and downstream products of Thieno[3,2-b]thiophene?
For Thieno[3,2-b]thiophene, Upstream Products: Thieno[3,2-b]thiophene-2-carboxylic acid, 3-Bromothiophene-2-carbaldehyde, Ethyl thieno[3,2-b]thiophene-2-carboxylate; Downstream Products: 3,6-dibromothieno[3,2-b]thiophene, 2,3,5-tribromothieno[3,2-b]thiophene, Methyl thieno[3,2-b]thiophene-2-carboxylate.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "Thieno[3,2-b]thiophene (CAS 251-41-2)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-40673-5 (accessed 2026-11-09).
Data for reference only; verify product details with suppliers before purchase.