Compound and thin film transistor and electronic device

A thin film transistor comprising

• a gate electrode,
• an organic semiconductor overlapping with the gate electrode, and
• a source electrode and a drain electrode electrically connected to the organic semiconductor,
• the organic semiconductor including a compound represented by Chemical Formula 1A or 1B,
• wherein, in Chemical Formulae 1A and 1B,
• X1 and X2 are different from each other and are independently one of O, S, Se, and Te, provided that one of X1 and X2 is Se or Te,
• R1 to R4 are independently one of hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 aryloxy group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, or a combination thereof, provided that R1 and R2 are different from each other, and
• n1 is an integer ranging from 2 to 4, and
• substituted refers to replacement of hydrogen of a group by a substituent selected from a halogen atom, a hydroxy group, a nitro group, a cyano group, an amino group, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group, an ester group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C3 to C30 heteroaryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and a combination thereof.