Ismail Khan began his service in the Russian Imperial Army on 1 May 1839 in Warsaw in the Transcaucasian Muslim Horse Regiment naibom (as assistant commander of a Sotnia).

Later he took part in the actions of the area Abas-gel, Mysun, Dutakh, Diadin, Kara-kilis, Alashkert (Toprak-kala), etc.

On 5 May 1877, by the order of the commander-in-chief of the Caucasian Army, the Grand Duke Michael Nikolaevich of Russia, the Colonel Ismail Khan was appointed commander of the newly formed Erivan Equestrian Irregular Regiment.

The brigade had the task of covering the state border from an eventual invasion of the enemy into the territory of the Erivan province.

On 4 June, the Major General Kelbali Khan, having received the information from the Lieutenant Colonel Patsevich about the movement of the Turks from Van to Bayazet, turned to the head of the Erivan detachment, the General Tergukasov, for permission to send reinforcements to Bayazet's garrison, but he was refused.

[5] The next day Patsevich informed Kelbali Khan that the Turkish cavalry was reconnoitring the roads to Bayazet, and asked for help.

Faced with many times superior enemy troops, Patsevich's detachment, suffering serious losses, began to retreat to the fortress.

At that moment, hundreds of the Erivan irregular cavalry regiment, led by Ismail Khan approached Bayazet after many hours of march.

From the report of the commandant of Bayazet, the captain F. E Shtokvich, to His Imperial Highness, the Commander-in-Chief of the Caucasian Army, the Grand Duke Mikhail Nikolaevich, dated with 4 July 1877, No.

116: The enemy, up to 7 thousand in number, makes a roundabout movement along the ridge of Kizil-dag in order to cut off our retreat to the city.

Ismail Khan made a quick movement to the left, hurried his hundreds and, having taken a good position, stopped the roundabout movement with well-aimed fire, holding the enemy for two hours ... - from the report of the commandant of the city of Bayazet, the captain Stockvich[7]When the retreating column, firing back, approached the fortress gate, it was blocked by a large herd of donkeys laden with breadcrumbs, since the fortress food master decided to move his warehouses from the city to the citadel on that very day.

Despite the heavy losses, the surviving part of Patsevich's detachment and the hundreds of remnants of Ismail Khan still managed to retreat to the citadel under the protection of the fortress walls.

The garrison of the fortress consisted of six infantry companies, three hundred Cossacks, two guns and the remnants of the Erivan irregular equestrian regiment.

From Ismail Khan's reminiscences: There was no positive information about Tergukasov's detachment; on the contrary, rumours penetrated into the garrison that it was surrounded and almost destroyed, which took away any hope for the outside help, and, of course, could influence the mood of the people to a certain extent ...In the conversations with me, the Lieutenant Colonel Patsevich and two or three other people have repeatedly spoken out in the sense that the outcome of our staying can only be inevitable death, if we do not capitulate.

— "Defence of Bayazet - the story of the Lieutenant-General Khan Nakhchivanski", the newspaper "Caucasus", 12 April 1895[8]On the third day of the blockade, the heat, thirst and hunger began to drive the besieged into despair.

On the morning of 8 June, the Turks, in large forces under the leadership of the former commandant of the city Kamal Ali Pasha, launched a powerful attack on the citadel.

Succumbing to panic, the Lieutenant Colonel Patsevich, with the consent of a number of other officers, including the fortress commandant Shtokvich, decided to surrender Bayazet.

- Patsevich raised a white flag and a huge mass of Turks has already rushed to our gate, - the officer explained.

- "Defense of Bayazet - the story of the Lieutenant-General Khan Nakhchivanski", the newspaper "Caucasus", 12 April 1895.From that moment, in fact, having dismissed the Lieutenant Colonel Patsevich, the Colonel Ismail Khan Nakhchivanski, as a senior in rank, on his own initiative, took over the commandment of Bayazet's garrison.

After the white flag was torn down and the attack of the Turks was repulsed, Ismail Khan appointed the military foreman of the 2nd Khopersky Regiment of the Kuban Cossack Army, Olympiy Nikitich Kvanin, as his assistant in carrying out all orders for the defence of Bayazet.

Having assumed the command of the garrison, Ismail Khan Nakhchivanski organized the defence of the fortress and in difficult conditions, without water and provisions, held it until the main forces of the Russian army approached.

By the highest order of 19 December 1877, "for military distinction", he was awarded the rank of Major General, and on 31 December 1877, "for exemplary and bravery management shown during the blockade of Bayazet in June 1877", he was awarded the Order of the "Saint Great Martyr and Victorious George of the IV degree”.

From a telegram from the Minister of War: "The Sovereign Emperor, on the occasion of the fiftieth anniversary of your service in the officer ranks, has most mercifully deigned you to be promoted to Lieutenant General, with the retention of the Caucasian Military District with the troops and with the increased salary according to the rank of 2,034 rubles a year.

The hero of Bayazet's defence, the Cavalry General Ismail Khan Nakhchivanski, died on 10 February 1909 in his hometown - Nakhichevan.