Table 1.

The general structural formulas of the various formazans covered in this review together with their biological activities which have been evaluated.

No.	General structure	Their screened biological activities
I	Ar—C( NNHAr′)—N N—Ar″	Anti-oxidant, anticonvulsant, antiviral. anti-inflammatory Antimicrobial, antiparkinsonian, analgesic
II	Ar—C( NNHAr′)—N N—Het	Anticonvulsant, antiviral. antimicrobial, antiparkinsonian, antiproliferative
III	Het—C( NNHAr′)—N N—Ar″	Antiviral
IV	Ar—C( NNH—CO—Ar′)—N N—Ar″	Anthelmintic, anti-inflammatory, anticancer, anti-HIV, antimicrobial, analgesic
V	Ar—C( NNH—CO—Het)—N N—Ar″	Anti-oxidant, Antitubercular, Antimicrobial
VI	Het—C( NNH—CO—Ar′)—N N—Ar″	Antiviral, anti-inflammatory
VII	Het—C( NNH—CO—Ar′)—N N—Het′	Antimicrobial
VIII	Ar—C( NNH—R)—N N—Ar″	Anti-inflammatory antimicrobial, antiparkinsonian, cardiovascular
IX	Ar—C( NN—Het)—N N—Ar″	Antiviral, anti-inflammatory, antimicrobial