A theranostic system comprising: a beacon in combination with or complexed to at least one compound selected from the group consisting of a quinazoline-based tyrosine kinase inhibitor and a natural product; wherein the beacon is a heterometallic compound of the general structure defined by Formula A wherein R 1a, R 1b and R 1c each independently represent a hydrogen atom or an optionally substituted alkyl or acyl group; Ln 3+ is a trivalent lanthanide metal; TM is a transition metal capable of near infrared emission; X is a negatively charged counterion; Z is represented by O, NH, S, a poly(ethylene glycol) linker, a C 1 -C 20 aliphatic chain or a conjugate of a poly(ethylene glycol) linker with a C 1 -C 20 aliphatic chain, wherein the poly(ethylene glycol) linker and the C 1 -C 20 aliphatic chain are conjugated via a peptidic or esteric bond; and n is 2; wherein the quinazoline-based tyrosine kinase inhibitor has the general structure defined by Formula I wherein R 1 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, N(R a)(R b), SR a or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; R 2 represents a hydrogen atom, a halogen atom, OR a, SR a, N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and R 3 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, SR a or N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; wherein R a and R b each independently represent a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and wherein the natural product is a chromanol of the vitamin E superfamily, selected from α-, β-, γ-, and δ-tocopherols, α-, β-, γ-, and δ-tocotrienols. a beacon in combination with or complexed to at least one compound selected from the group consisting of a quinazoline-based tyrosine kinase inhibitor and a natural product; wherein the beacon is a heterometallic compound of the general structure defined by Formula A wherein R 1a, R 1b and R 1c each independently represent a hydrogen atom or an optionally substituted alkyl or acyl group; Ln 3+ is a trivalent lanthanide metal; TM is a transition metal capable of near infrared emission; X is a negatively charged counterion; Z is represented by O, NH, S, a poly(ethylene glycol) linker, a C 1 -C 20 aliphatic chain or a conjugate of a poly(ethylene glycol) linker with a C 1 -C 20 aliphatic chain, wherein the poly(ethylene glycol) linker and the C 1 -C 20 aliphatic chain are conjugated via a peptidic or esteric bond; and n is 2; wherein R 1a, R 1b and R 1c each independently represent a hydrogen atom or an optionally substituted alkyl or acyl group; Ln 3+ is a trivalent lanthanide metal; TM is a transition metal capable of near infrared emission; X is a negatively charged counterion; Z is represented by O, NH, S, a poly(ethylene glycol) linker, a C 1 -C 20 aliphatic chain or a conjugate of a poly(ethylene glycol) linker with a C 1 -C 20 aliphatic chain, wherein the poly(ethylene glycol) linker and the C 1 -C 20 aliphatic chain are conjugated via a peptidic or esteric bond; and n is 2; wherein the quinazoline-based tyrosine kinase inhibitor has the general structure defined by Formula I wherein R 1 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, N(R a)(R b), SR a or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; R 2 represents a hydrogen atom, a halogen atom, OR a, SR a, N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and R 3 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, SR a or N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; wherein R a and R b each independently represent a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and wherein R 1 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, N(R a)(R b), SR a or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; R 2 represents a hydrogen atom, a halogen atom, OR a, SR a, N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and R 3 represents a hydrogen atom, a halogen atom, N 3, CN, NO 2, OR a, SR a or N(R a)(R b), or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; wherein R a and R b each independently represent a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, acyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, heterocyclyl or heterocyclylalkyl group; and wherein the natural product is a chromanol of the vitamin E superfamily, selected from α-, β-, γ-, and δ-tocopherols, α-, β-, γ-, and δ-tocotrienols.