Disclosed is a furochrome of formula (I) where the substituents are as disclosed in the description. Examples of compounds of the invention are: 7-Dimethylaminomethyl-9-[3-R-(3-(phenyl)butoxy)]-4-methyl-5H-furo[3,2-g]chromen-5-one 7-Dimethylaminomethyl-9-(3[4-fluorophenyl]propoxy)-4-methyl-5H-furo[3,2-g]chromen-5-one 4-Methyl-7-methylsulfanylmethyl-9-(3-phenylpropoxy)furo[3,2-g]chromen-5-one. Also disclosed is a pharmaceutical composition comprising a compound of formula (I) and the use of a compound of formula (I) in the manufacture of a medicament for treating autoimmune or chronic inflammatory diseases, or the prevention of rejection of foreign organ transplants and/or related afflictions. Further disclosed is a method of intentionally modulating potassium ion channel activity of T-cells ex vivo by the application of a compound of formula (I)
