summary "pyrrolobenzodiazepines and conjugates thereof" means a compound of formula I: and salts and solvates thereof, wherein: when there is a double bond present between c2 and c3, r2 is selected from the group consisting of: (ia) group C 5-10 aryl, optionally substituted by one or more substituents selected from the group comprising: halo, nitro, cyano, ether, C 1-7 alkyl, C 3-7 heterocyclyl and bis-oxyC 1-3 alkylene； (ib) saturated aliphatic C1-5 alkyl； (ic) saturated C 3-6 cycloalkyl； (id), wherein each of r11, r12 and r13 is independently selected from h, saturated C1-3 alkyl, c2-3 alkenyl, c2-3 alkynyl and cyclopropyl, where the total number of carbon atoms in group r2 is not larger than 5； (ie), wherein one of r15a and r15b is h and the other is selected from: phenyl, phenyl which is optionally substituted by a group selected from halo, methyl, methoxy, pyridyl； and thiophenyl； and (if), where r14 is selected from: h； saturated C1-3 alkyl； C 2-3 alkenyl； c2-3 alkynyl； cyclopropyl； phenyl, phenyl which is optionally substituted by a group selected from halo, methyl, methoxy； pyridyl； and thiophenyl； when there is a single bond present between c2 and c3, r2 e, where r16a and r16b are independently selected from h, f, saturated C1-4 alkyl, c2-3 alkenyl, these alkyl and alkenyl groups which are optionally substituted by a selected group from C 1-4 alkyl starch and C 1-4 alkyl ester； or, when one of r16a and r16b is h, the other is selected from nitrile and a C1-4 alkyl ester； when there is a double bond present between c2 'and c3', r12 is selected from the group consisting of: (ia) aryl group c5-10, optionally substituted by one or more substituents selected from the group comprising: halo, nitro, cyano carboxy, ester, C 1-7 alkyl, C 3-7 heterocyclyl and bis-oxyC 1-3 alkylene； (ib) saturated aliphatic C1-5 alkyl； (ic) saturated C 3-6 cycloalkyl； (id), wherein each of r21, r22 and r23 is independently selected from h, saturated C1-3 alkyl, c2-3 alkenyl, c2-3 alky
