A non-therapeutic method of modulating perforin activity, on a cell, said method including the step of exposing the cell to a compound of the formula: wherein Ring A is selected from a 6-10 membered aryl, 5-6 membered cycloalkyl, 5-6 membered heteroaryl or 5-6 membered heterocyclyl, wherein the heteroaryl and heterocyclyl rings comprise at least one heteroatom selected from N, O or S; and wherein the aryl, cycloalkyl, heteroaryl or heterocyclyl rings are optionally substituted with 1 to 3 substituents selected from halo, nitro, cyano, -C 1 -C 6 alkyl, -C 1 -C 6 aminoalkyl, -C 1 -C 6 hydroxyalkyl, -haloC 1 -C 6 alkyl, -C 1 -C 6 alkoxyl, -haloC 1 -C 6 alkoxyl, heteroaryl, aryl, hydroxyl, -C C 1 -C 6 alkyl, -OC C 1 -C 6 alkyl, -CH 2 OC C 1 -C 6 alkyl, -C OC 1 -C 6 alkyl, -NHC C 1 -C 6 alkyl, -NHS 2 C 1 -C 6 alkyl, -S 2 C 1 C 6, -S 2 NH 2, and -C NJJ; Ring B is a 6-10 membered arylene or a 5-6 membered heteroarylene comprising at least one heteroatom selected from N, O or S; and wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from -NJJ, -OJ, halo, -C 1 -C 6 alkyl, -haloC 1 -C 6 alkyl, -C 1 -C 6 alkoxy, haloC 1 -C 6 alkoxy, and - C NJJ; Ring C is selected from a 5-10 membered heteroarylene or a 5-10 membered heterocyclene, each comprising at least one heteroatom selected from N, S and O; Ring D is an optionally substituted 6-11 membered heterocyclyl or optionally substituted 6-11 membered heteroaryl comprising at least one heteroatom selected from N or O; L is a linker selected from branched or unbranched C 1 -C 4 alkylene, -S 2 -NH-, -C -NH-, -NH-C -NH-, -S 2 -NH-C -NH-, -S 2 -NH-C -, -C -NH-C -NH- and-CH=CH-; wherein Rings B and C, and Rings C and D, are connected to each other via a C-C bond at any of the available C atoms on each respective ring; and J in each occurrence is independently selected from H, optionally substituted C 1 -C 6 alkyl or optionally substituted haloC 1 -C 6 alkyl; and pharmaceutically acceptable salts, solvates, and hydrates thereof. Ring A is selected from a 6-10 membered aryl, 5-6 membered cycloalkyl, 5-6 membered heteroaryl or 5-6 membered heterocyclyl, wherein the heteroaryl and heterocyclyl rings comprise at least one heteroatom selected from N, O or S; and wherein the aryl, cycloalkyl, heteroaryl or heterocyclyl rings are optionally substituted with 1 to 3 substituents selected from halo, nitro, cyano, -C 1 -C 6 alkyl, -C 1 -C 6 aminoalkyl, -C 1 -C 6 hydroxyalkyl, -haloC 1 -C 6 alkyl, -C 1 -C 6 alkoxyl, -haloC 1 -C 6 alkoxyl, heteroaryl, aryl, hydroxyl, -C C 1 -C 6 alkyl, -OC C 1 -C 6 alkyl, -CH 2 OC C 1 -C 6 alkyl, -C OC 1 -C 6 alkyl, -NHC C 1 -C 6 alkyl, -NHS 2 C 1 -C 6 alkyl, -S 2 C 1 C 6, -S 2 NH 2, and -C NJJ; Ring B is a 6-10 membered arylene or a 5-6 membered heteroarylene comprising at least one heteroatom selected from N, O or S; and wherein the aryl or heteroaryl is optionally substituted with one or more substituents selected from -NJJ, -OJ, halo, -C 1 -C 6 alkyl, -haloC 1 -C 6 alkyl, -C 1 -C 6 alkoxy, haloC 1 -C 6 alkoxy, and - C NJJ; Ring C is selected from a 5-10 membered heteroarylene or a 5-10 membered heterocyclene, each comprising at least one heteroatom selected from N, S and O; Ring D is an optionally substituted 6-11 membered heterocyclyl or optionally substituted 6-11 membered heteroaryl comprising at least one heteroatom selected from N or O; L is a linker selected from branched or unbranched C 1 -C 4 alkylene, -S 2 -NH-, -C -NH-, -NH-C -NH-, -S 2 -NH-C -NH-, -S 2 -NH-C -, -C -NH-C -NH- and-CH=CH-; wherein Rings B and C, and Rings C and D, are connected to each other via a C-C bond at any of the available C atoms on each respective ring; and J in each occurrence is independently selected from H, optionally substituted C 1 -C 6 alkyl or optionally substituted haloC 1 -C 6 alkyl; and pharmaceutically acceptable salts, solvates, and hydrates thereof.