With the CAS registry number 51856-25-8, this chemical's molecular formula is C₇H₅NO₂S and molecular weight is 167.19. What's more, its systematic name is 6H-Thieno[2,3-b]pyrrole-5-carboxylic acid. 

Physical properties of 6H-Thieno[2,3-b]pyrrole-5-carboxylic acid are: (1)ACD/LogP: 3.24; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 1.96; (4)ACD/LogD (pH 7.4): 0.39; (5)ACD/BCF (pH 5.5): 9.03; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 72.96; (8)ACD/KOC (pH 7.4): 1.93; (9)#H bond acceptors: 3; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 1; (12)Polar Surface Area: 59.47 Å²; (13)Index of Refraction: 1.786; (14)Molar Refractivity: 43.84 cm³; (15)Molar Volume: 103.8 cm³; (16)Polarizability: 17.38×10^-24 cm³; (17)Surface Tension: 85.6 dyne/cm; (18)Density: 1.609 g/cm³; (19)Flash Point: 218.3 °C; (20)Enthalpy of Vaporization: 73.15 kJ/mol; (21)Boiling Point: 437.4 °C at 760 mmHg; (22)Vapour Pressure: 2E-08 mmHg at 25°C.

You can still convert the following datas into molecular structure:
(1)SMILES: O=C(O)c2cc1c(scc1)n2
(2)InChI: InChI=1S/C7H5NO2S/c9-7(10)5-3-4-1-2-11-6(4)8-5/h1-3,8H,(H,9,10)
(3)InChIKey: SEPXFZLYPWFMSY-UHFFFAOYSA-N