A 1,4-Dimethyltetrazene selected from: - β-functionalized 1,4-dimethyltetrazenes of formula (Ia): R1-CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -R2 (Ia) wherein R1 = R2 = -CH 2 Cl, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , or -CH 2 NCO ; or R1 and R2, which are identical, comprising an ether group, are selected from the following pairs: R1 = R2 = -CH 2 O-CH 2 -CH=CH 2 , R1 = R2 = -CH 2 O-CH 2 -C≡CH, et R1 = R2 = -CH 2 O-CH 2 -C≡N ; - γ-functionalized 1,4-dimethyltetrazenes of formula (Ib): R3-CH 2 -CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -CH 2 -R4 (Ib) wherein R3 = R4 = -CH 2 OH, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , -CH 2 NCO, -CH 2 CN or -CH 2 ONO 2 , or R3 = -CH 2 OH and R4 = -CH 2 N 3 , or R3 = -CH 2 CN and R4 = -CH 2 N 3 , or R3 = -CH 2 N 3 and R4 = -CH 2 N(CH 3 )(NH 2 ), or R3 and R4, identical or different, at least one of which containing an ether group, are selected from the following pairs: R3 = R4 = -CH 2 O-CH 2 -CH=CH 2 R3 = R4 = -CH 2 O-CH 2 -C≡CH R3 = R4 = -CH 2 O-CH 2 -C≡N R3 = -CH 2 O-CH 2 -CH=CH 2 and R4 = -CH 2 N 3 R3 = -CH 2 O-CH 2 -C≡CH and R4 = -CH 2 N 3 , and R3 = -CH 2 O-CH 2 -C≡N and R4 = -CH 2 N 3 ; and - β,γ-functionalized 1,4-dimethyltetrazenes of formula (Ic): R5-CHOH-CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -CHOH-R5 (Ic) wherein R5 = -CH 2 N 3 or -CH 2 CN. - β-functionalized 1,4-dimethyltetrazenes of formula (Ia): R1-CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -R2 (Ia) wherein R1 = R2 = -CH 2 Cl, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , or -CH 2 NCO ; or R1 and R2, which are identical, comprising an ether group, are selected from the following pairs: R1 = R2 = -CH 2 O-CH 2 -CH=CH 2 , R1 = R2 = -CH 2 O-CH 2 -C≡CH, et R1 = R2 = -CH 2 O-CH 2 -C≡N ; R1 = R2 = -CH 2 Cl, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , or -CH 2 NCO ; or R1 and R2, which are identical, comprising an ether group, are selected from the following pairs: R1 = R2 = -CH 2 O-CH 2 -CH=CH 2 , R1 = R2 = -CH 2 O-CH 2 -C≡CH, et R1 = R2 = -CH 2 O-CH 2 -C≡N ; R1 = R2 = -CH 2 O-CH 2 -CH=CH 2 , R1 = R2 = -CH 2 O-CH 2 -C≡CH, et R1 = R2 = -CH 2 O-CH 2 -C≡N ; - γ-functionalized 1,4-dimethyltetrazenes of formula (Ib): R3-CH 2 -CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -CH 2 -R4 (Ib) wherein R3 = R4 = -CH 2 OH, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , -CH 2 NCO, -CH 2 CN or -CH 2 ONO 2 , or R3 = -CH 2 OH and R4 = -CH 2 N 3 , or R3 = -CH 2 CN and R4 = -CH 2 N 3 , or R3 = -CH 2 N 3 and R4 = -CH 2 N(CH 3 )(NH 2 ), or R3 and R4, identical or different, at least one of which containing an ether group, are selected from the following pairs: R3 = R4 = -CH 2 O-CH 2 -CH=CH 2 R3 = R4 = -CH 2 O-CH 2 -C≡CH R3 = R4 = -CH 2 O-CH 2 -C≡N R3 = -CH 2 O-CH 2 -CH=CH 2 and R4 = -CH 2 N 3 R3 = -CH 2 O-CH 2 -C≡CH and R4 = -CH 2 N 3 , and R3 = -CH 2 O-CH 2 -C≡N and R4 = -CH 2 N 3 ; and R3 = R4 = -CH 2 OH, -CH 2 N 3 , -CH 2 NH 2 , -CH 2 N(CH 3 )(NH 2 ), -CH=CH 2 , -CH 2 NCO, -CH 2 CN or -CH 2 ONO 2 , or R3 = -CH 2 OH and R4 = -CH 2 N 3 , or R3 = -CH 2 CN and R4 = -CH 2 N 3 , or R3 = -CH 2 N 3 and R4 = -CH 2 N(CH 3 )(NH 2 ), or R3 and R4, identical or different, at least one of which containing an ether group, are selected from the following pairs: R3 = R4 = -CH 2 O-CH 2 -CH=CH 2 R3 = R4 = -CH 2 O-CH 2 -C≡CH R3 = R4 = -CH 2 O-CH 2 -C≡N R3 = -CH 2 O-CH 2 -CH=CH 2 and R4 = -CH 2 N 3 R3 = -CH 2 O-CH 2 -C≡CH and R4 = -CH 2 N 3 , and R3 = -CH 2 O-CH 2 -C≡N and R4 = -CH 2 N 3 ; and R3 = R4 = -CH 2 O-CH 2 -CH=CH 2 R3 = R4 = -CH 2 O-CH 2 -C≡CH R3 = R4 = -CH 2 O-CH 2 -C≡N R3 = -CH 2 O-CH 2 -CH=CH 2 and R4 = -CH 2 N 3 R3 = -CH 2 O-CH 2 -C≡CH and R4 = -CH 2 N 3 , and R3 = -CH 2 O-CH 2 -C≡N and R4 = -CH 2 N 3 ; and - β,γ-functionalized 1,4-dimethyltetrazenes of formula (Ic): R5-CHOH-CH 2 -N(CH 3 )-N=N-N(CH 3 )-CH 2 -CHOH-R5 (Ic) wherein R5 = -CH 2 N 3 or -CH 2 CN. <EOS>